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Die Universitat Koblenz-Landau stellt sich in vielfaltiger Weise ihrer gesellschaftlichen Verantwortung. Als Beispiele fur die uber ihre Kernaufgaben in Forschung und Lehre hinausgehend wahrgenommene Corporate Social Responsibility werden hier unter dem Nachhaltigkeitsziel Bildungsteilhabe die sehr gut etablierten auserschulischen Lernstandorte sowie die Ansatze im Bereich Open Educational Ressources OER vorgestellt.

We quantify the effects of combined precipitating solar protons and magnetospheric electrons on nighttime odd hydrogen density enhancements during two solar energetic particle (SEP) events accompanied by strong geomagnetic storms. We perform detailed modeling of ionization rates for 7–17 November 2004 and 20–30 August 2005 intervals with improved version 1.6 of the Atmospheric Ionization Module Osnabruck model. Particle measurements from Geostationary Operational Environmental Satellites and Polar Orbiting Environmental Satellites are sorted and combined in 2 h intervals to create realistic particle precipitation maps that are used as the modeling input. We show that modeled atmospheric ionization rates and estimated peak odd hydrogen (primarily hydroxyl) production from 0.001 hPa to 0.1 hPa atmospheric pressure levels during these intervals are consistent with enhancements in nighttime averaged zonal odd hydrogen densities derived from newly reprocessed and improved data set of Microwave Limb Sounder instrument on board Aura satellite. We show that both precipitating SEPs and magnetospheric electrons contribute to mesospheric ionization and their relative contributions change throughout the intervals. Our event-based modeling results underline the importance of the combined ionization sources for odd hydrogen chemistry in the middle atmosphere.

As a result of increasing public and political interest in ‘space’ (i.e. solar system) exploration at the global scale, the Space Advisory Group of the European Commission has evaluated the situation in Europe with regard to its potential to participate in this ambitious global enterprise. Aspects of science, technology, environment and safety, society, spin-offs and international cooperation were all considered. The group concluded that Europe possesses sufficient key technologies and scientific expertise to play a major role in international space exploration and has recommended that the EU take a central role to ensure the success of future European space exploration, not only to give a clear political signal for the way forward but also to ensure an appropriate financial framework. In this way Europe would embrace the spirit of the European Space Policy and contribute to the knowledge-based society by investing significantly in space-based science and technology, thereby playing a strong role in international space exploration.

The precipitation of solar energetic particles, protons as well as electrons, at high latitudes is commonly assumed to be homogeneous across both polar caps. Using Low-Earth Orbit POES (Polar Orbiting Environmental Satellites) we determine particle penetration ratios into the polar atmosphere for protons ranging from about 0.1 MeV to 500 MeV and for electrons spanning about one order of magnitude in energy with a maximum of 0.3 MeV. Based on power law fits for the POES spectrum we show, that for energies interesting for middle and lower atmosphere chemistry, particle flux over the poles is comparable in magnitude to flux at the geostationary orbit or at L1 in interplanetary space. The time period under study are the solar energetic particle (SEP) event series of October/November 2003 and January 2005.

In previous studies, transport of solar energetic particles in the inner heliosphere was regarded as one-dimensional along the Archimedean field spiral; i.e., any perpendicular transport is neglected. We extend Roelof’s equation of focused transport for solar energetic particles to accommodate perpendicular transport in the plane of the ecliptic. Numerically, this additional term is solved with an implicit Laasonen scheme. In this first approximation, it is solved for azimuthal instead of perpendicular transport – these are similar in the inner heliosphere where the Archimedean field is almost radial. The intent of the study is to estimate the possible influence of perpendicular transport, but not to fit energetic particle events; thus, the particle source stays fixed on the Sun. For typical ratios κ ⊥ /κ ‖ between 0.02 and 0.1 at 1 AU scaled with r 2 as suggested in nonlinear guiding-center theory, we find that i) an azimuthal spread over some 10° occurs within a few hours, ii) the variation of maximum intensities with longitude is comparable to the ones inferred from multispacecraft observations, and iii) on a given field line, intensity and anisotropy-time profiles are modified such that fits with the two-dimensional transport model give different combinations of injection profiles and mean free paths. Implications for the interpretation of intensity and anisotropy-time profiles observed in interplanetary space and consequences for our understanding of particle propagation and acceleration in space are discussed.

The detailed study of the precipitation of magnetospheric particles into the atmosphere is complicated by the rather complex spatial configuration of the precipitation region and its variability with geomagnetic activity. In this paper we will introduce polar oval coordinates and apply them to POES observations of 30 keV to 2.5 MeV electrons and comparable protons to illustrate the dependence of particle precipitation on local time and geomagnetic activity. These coordinates also allow an easy separation of the spatial precipitation patterns of solar and magnetospheric particles. The results indicate that (a) the spatial precipitation pattern of energetic magnetospheric electrons basically follows the pattern of the field parallel Birkeland currents up to MeV energies and (b) at least in the mesosphere the influence of magnetospheric electrons is comparable to the one of solar electrons. Implications for modeling of atmospheric chemistry will be sketched.

We study the radial and longitudinal dependence of 4-13 and 27-37 MeV proton peak intensities and fluences measured within 1 AU of the Sun during intense solar energetic particle events. Data are from the IMP 8 and the two Helios spacecraft. We analyze 72 events and compute the total event fluence (F) and the peak intensity (J), distinguishing between the event's absolute maximum intensity and that neglecting local increases associated with the passage of shocks or plasma structures. Simultaneous measurements of individual events by at least two spacecraft show that the dominant parameter determining J and F is the longitudinal separation () between the parent active region and the footpoint of the field line connecting each spacecraft with the Sun, rather than the spacecraft radial distance (R). We perform a multiparameter fit to the radial and longitudinal distributions of J and F for events with identified solar origin and that produce intensity enhancements in at least two spacecraft. This fit determines simultaneously the radial and longitudinal dependences of J and F. Radial distributions of events observed by at least two spacecraft show ensemble-averaged variations ranging from R-2.7 to R-1.9 for 4-13 and 27-37 MeV proton peak intensities, and R-2.1 to R-1.0 for 4-13 and 27-37 MeV proton event fluences, respectively. Longitudinal distributions of J and F are approximated by the form e, where 0 is the distribution centroid and k is found to vary between ~1.3 and ~1.0 rad-2. Radial dependences are less steep than both those deduced from diffusion transport models by Hamilton et al. in 1990 and those recommended by Shea et al. in 1988 to extrapolate J and F from R = 1 to R < 1 AU.

Precipitating solar energetic particles (SEPs) ionize the atmosphere. They produce NOx and HOx which in turn destroy ozone. Here, we present Monte-Carlo simulations of the SEP interaction with the atmosphere. Compared to continuous energy loss models, the Monte-Carlo method leads to a shift of ionization to lower altitudes because secondaries, in particular X-rays produced by electron bremsstrahlung, are considered. In addition, the inclusion of ionization by solar electrons leads to modifications in ion production profiles with the magnitude of the effect depending on the properties of the parent solar event. Implications of our results for atmospheric chemistry modeling are briefly sketched.

The Ulysses spacecraft at high heliographic latitudes has detected eight large solar energetic particle events during the recent solar maximum in 2000 and 2001 years. These events are easily identified with famous episodes of the solar activity and the corresponding SEP events near the Earth. Analyzing the absolute intensities of ∼40–100 MeV proton time profiles from the Ulysses COSPIN/KET and the GOES detector near Earth we find that for these eight events the intensities vary only within a factor of 2–3 from event to event at high latitudes during the first 30 h. In contrast the intensities at Earth differ from one event to another by several orders of magnitude. Thus, the time history during these 30 h has only a weak dependence on the relative position of Ulysses to the possible flare location. This implies: (1) a nearly isotropic injection of protons with comparable intensities to high heliolatitudes, and (2) a similar propagation process during the first 30 h of the events. We attribute the fact that the decay phases of these events are nearly the same at Ulysses and in the ecliptic rather to cross-field diffusion than to the presence of a shock.

Solar energetic particles (SEPs) are one manifestation of violent energy releases on the Sun. The study of their acceleration and propagation reveals information about basic plasma-physical processes, such as reconnection, shock acceleration and wave–particle interaction, in astrophysical objects, such as stars, magnetospheres or the diluted plasma of the interstellar or interplanetary medium. This paper introduces the current classification scheme for solar energetic particle events, its relation to the underlying acceleration processes, and addresses open questions regarding the better understanding of SEPs as well as the underlying physical processes. Modifications to the current paradigm considering more recent observations will be suggested.

Magnetic clouds modify the structure of the interplanetary magnetic field on spatial scales of tenth of AU. Their influence on the transport of energetic charged particles is studied with a numerical model that treats the magnetic cloud as an outward propagating modification of the focusing length. As a rule of thumb, the influence of the magnetic cloud on particle intensity and anisotropy profiles increases with decreasing particle mean free path and decreasing particle speed. Three cases are considered: (1) when the magnetic cloud is the driver of a shock that accelerates particles as it propagates outward, (2) when the magnetic cloud interacts with a prior solar energetic particle event, and (3) when a magnetic cloud already is present in interplanetary space at the time of a solar energetic particle event. In the latter case the cloud acts as a barrier, storing the bulk of the particles in its downstream medium.

This paper presents an expanded version of a numerical scheme to model the intensity and anisotropy time profiles of energetic particle events associated with interplanetary shocks. The acceleration at the shock is treated as a black box; the subsequent particle propagation is described in a transport model which in addition to the effects of focusing and pitch angle scattering also considers convection with the solar wind and adiabatic deceleration. In addition, the pitch angle transport associated with the passage of energetic particles through the shock is included. Owing to the special description of the shock, corotation is considered too. Results of the model with and without solar wind effects are compared. Owing to the continuous supply of fresh particles from the shock, the influence of solar wind effects is always smaller than that in the case of a simple solar injection for the same set of parameter values. Depending on the radial development of the shock efficiency and the location of the observer relative to the nose of the shock, at 1 AU the effects of adiabatic deceleration and convection are important only at energies below a few MeV. Solar wind effects always show a stronger influence on profiles observed at the shock's eastern flank than those close to the central meridian or on the western flank. Owing to the inclusion of adiabatic deceleration, particle profiles at different energies are coupled: the assumption of a rigidity dependent radial development of the shock's acceleration efficiency, that is, a steepening of the injection spectrum, is required to reproduce the observed energy dependence of intensity time profiles.

Energetic protons in the hundreds of keV to the tens of MeV range frequently are observed in connection with traveling interplanetary shocks. Occasionally, the particle energies can extend up to about 100 MeV. The intensity time profiles at the observer's site are a superposition of the continuous, spatially and temporally variable acceleration at the shock and the subsequent interplanetary propagation. To gain a better understanding of both processes and to derive their relevant parameters, we extend a numerical solution of the model of focused transport to accommodate the shock as a moving source. No assumptions about the acceleration mechanism are made; the shock is treated as a black box. In this paper we introduce the model, discuss its validity, and present model results which have implications for acceleration theory and data interpretation. The main results concerning acceleration and propagation are as follows: (1) In the limit of strong scattering and low particle speeds our model converges toward diffusive shock acceleration. (2) For weak scattering or fast particles, spatial diffusion is an insufficient approximation for particle transport; in this case, the physical consequence is a fast escape from the shock, and the formal consequence is that the standard description of diffusive shock acceleration is insufficient. (3) Because of this fast escape, even a turbulent foreshock region, while it is perfectly capable of keeping 100 keV protons confined to the shock, would allow 10 MeV protons to stream away easily. Important results for data interpretation are as follows: (1) A quasi-exponential intensity increase upstream of the shock is not necessarily indicative of diffusive shock acceleration. (2) The intensity at the time of shock passage is a crude measure for the local acceleration efficiency as long as it stays constant or continues to rise. Copyright 1997 by the American Geophysical Union.

Particle events observed in association with interplanetary shocks exhibit a wide variety of different features. In this paper we will demonstrate how these features can be understood in terms of a spatially and temporally varying shock efficiency and the subsequent interplanetary propagation. The examples presented here will show that while the location of the observer relative to the shock is an important factor in determining the event properties, the radial and temporal evolution of the shock also plays an important role. In particular, there are shocks which in a given energy range predominately accelerate particles close to the Sun, while in others the shock efficiency increases as they propagate outward. Another goal of this paper is to demonstrate that the black box model used here is able to fit the data. Copyright 1997 by the American Geophysical Union.

Between 1974 and 1985 the two Helios spacecraft observed 351 transient interplanetary shocks. For 5-MeV protons the particle events associated with these shocks can be divided into three groups : (1) events without intensity increase above quiet time or increased background (47%), (2) solar and interplanetary particle (SIP) events consisting of particles accelerated on or close to the Sun (solar or near-Sun component) as well as at the interplanetary shock (24%), and (3) pure interplanetary particle (PIP) events (29%) which consist of particles accelerated at the shock in interplanetary space but do not show evidence for significant or even excess particle acceleration on the Sun. This classification shows that (1) only about half of the shocks accelerate MeV protons in interplanetary space and (2) MeV protons accelerated on the Sun are neither a necessary nor a sufficient condition for the acceleration of MeV protons in interplanetary space. Shock parameters such as speed or shock strength alone do not give an indication for the class of the associated particle event, because in the parameter range which covers most of the shocks, all three classes are distributed rather evenly. However, the shocks strongest in these parameters tend to accelerate particles. The intensity at the time of shock passage, which can be used as a crude measure for the local acceleration efficiency, is correlated with the local shock speed and the magnetic compression. The correlation coefficients are small but statistically significant, indicating that (1) the correlations are real and (2) the intensity is influenced by additional parameters, which are not necessarily shock inherent. As an example I will show that the local acceleration at the shock decreases roughly symmetrically with increasing distance from the nose of the shock with a median e-folding angle of 10°. Occasionally, larger e-folding angles are observed close to the nose of the shock. The question of how the shock accelerates protons in the MeV range could not be answered here, but I will suggest future studies that could shed a new light on this problem.

Precipitating charged particles contribute to the natural variations in the Earth’s atmosphere such as ionization, electron density, and composition of e.g. NOx and Ozone. Precipitating solar energetic and magnetospheric particles show a highly dynamic behavior in space and time. We present a 3D ionization model considering the relevant particle species (electrons, protons, and alpha particles) as well as precipitation areas (polar cap and auroral oval): the Atmospheric Ionization Model OSnabruck AIMOS, and discuss some of the atmospheric consequences of precipitating particles. We present the limitations of direct comparisons between EISCAT and precipitating particles and give comparisons between incoherent scatter measurements and a combination of AIMOS and the HAMMONIA GCM to demonstrate the consistency in both methods.

Both particle propagation and acceleration are intimately related to the strength of scattering. I shall review some recent developments in our understanding of interplanetary propagation, in particular the dawn of a solution of the well-known discrepancy problem between mean free paths (mfp) derived from quasi-linear theory (QLT) and from fits to observational data. With this much improved understanding of particle scattering we can re-evaluate our understanding of particle acceleration at interplanetary shocks. Special attention is paid to the model of coupled hydrodynamic wave excitation and ion acceleration at shocks.

For 16 proton events in the 10 MeV energy range associated with interplanetary shocks we guesstimated the particle mean free paths (mfp) and the radial development of the particle injection at the shock using a numerical solution of the focused transport equation. The particle mfps derived by this method typically are larger than the mfps derived from the magnetic field power spectra and are comparable to the ones found in previous studies of solar energetic particle events. The evolution of the shocks acceleration efficiency can be highly variable with efficiencies varying as τα where α is between −2 and 2. In some cases α can be as large as 5 or more. These latter events show distinct features, in particular quasi-exponential particle increases and extremely weak proton spectra with spectral indices around −5 for protons with energies of a few to a few tens of MeV. In the 7 events with sufficient quality of the magnetic field data we find no indication of an increase of turbulence in the upstream medium at wave numbers in resonance with the particles.

The passage of interplanetary shocks frequently is associated with enhancements in energetic particles from supra-thermal energies up to energies of a few tens of MeV or even a hundred MeV. While these observations clearly indicate that interplanetary shocks are capable of efficient proton acceleration, the acceleration mechanism(s) are not completely understood. For the ‘low energy’ proton populations up to a few hundreds of keV, the observations are in good agreement with shock-drift acceleration at quasi-perpendicular and diffusive shock acceleration at quasi-parallel shocks. Both mechanisms, however, are not expected to be efficient accelerators for the higher energetic particle population. We will review observations of accelerated particles in different energy ranges, the different types of intensity profiles observed in connection with the passage of interplanetary shocks, and attempts to correlate the properties of the particle event with shock parameters to identify the crucial parameter(s) that determine the acceleration. Special attention will be paid to the similarities and differences between lower and higher energetic particles.

We study 27 increases of the flux of 300–800 keV electrons on board HELIOS A or B, associated with intense type III radio bursts close to perihelion passages of the two spacecraft, during the solar minimum. Electrons can be detected inside cones with an angular width between 30° and 60°. Though only intense type III bursts are associated with recognizable electron events in space, such an association does not exist for all of them; this fact and great differences in fluxes of the individual events indicate that, apart from the intensity, also some other charactefistic of the type III burst acceleration or propagation process determines the resulting flux of electrons in space; the energy spectrum of the accelerated electrons is one of the likely candidates. A comparison of the electron flux in these events with the flux of 1.7–3.7 MeV nucl−1 helium reveals very large variations of the helium/electron flux ratio, by a factor of at least 15 and possibly much higher. We demonstrate that these variations are not caused by propagation effects in interplanetary space. Therefore, they must be due either to propagation effects in the solar corona or, more likely, to intrinsic variations in the relative production of electrons and nuclei in the type III burst process. An extrapolation of the observed fluxes to 1 AU shows that in only 7 of the 27 electron events studied might a marginal > 1.7 MeV helium flux be recognized ar the Earth distance.

[1] Ionization of the atmosphere due to precipitating solar energetic particles as well as magnetospheric particles is a major source of thermospheric electron density. In this paper we evaluate numerical simulations of the 3-D spatial and temporal electron densities produced by these particle populations through a comparison with incoherent scatter radar observations. The 3-D precipitation patterns are determined with the Atmospheric Ionization Module Osnabruck (AIMOS). We use a version of the general circulation and chemistry model Hamburg Model of the Neutral and Ionized Atmosphere (HAMMONIA) enhanced by ion chemistry to calculate the impact of particle ionization on the electron density. These modeled data are compared to radar observations from European Incoherent Scatter Svalbard and Tromso as well as the incoherent scatter radar stations at Millstone Hill and Sondrestrom. Particle precipitation is severely affected by geomagnetic disturbance and latitude. Therefore, different locations (inside the polar cap and at auroral latitudes) and geomagnetic conditions are included in the comparison. The main results of the paper can be summarized as follows: (1) as expected, particle forcing will significantly improve modeled electron density in comparison to results of the radar measurements; (2) in particular nighttime comparisons of the electron density are affected; here the particle forcing will account for a boost of 2 to 3 orders of magnitude.

For 27 energetic particle events observed on one of the Helios spacecraft we present fits on the intensity and anisotropy time profiles performed with the model of focused transport. The events have local mean free paths λ∥ between 0.02 and ≥1 AU, for most events λ∥ lies within or above the consensus range between 0.08 and 0.3 AU. The propagation in general can be described as focused or diffusive transport, therefore in the majority of events interplanetary scattering plays an important role. Comparing with results from earlier studies we find that scatter-free events can be observed inside 0.5 AU as well as close to 1 AU, therefore extreme scattering properties seem not to be related to radial changes in scattering conditions. In addition, any radial variation in the scattering mean free path seems to be small compared to the event-to-event variations. A comparison of fits on ∼18-MeV protons and ∼1-MeV electrons shows that the scattering mean free path λp of the protons is related to the electron mean free path λe, whereby the average ratio λp/λe is 1.6±0.9. This latter observation has important consequences for our understanding of the underlying scattering mechanism, in particular as it is in contradiction with conventional results from quasi-linear theory.

We present a sample of solar energetic particle events observed between November 18 and December 31, 1982 by the HELIOS 1, the VENERA 13, and IMP 8 spacecraft. During the entire time period all three spacecraft were magnetically connected to the western hemisphere of the Sun with varying radial and angular distances from the flares. Eleven proton events, all of them associated with interplanetary shocks, were observed by the three spacecraft. These events are visible in the low-energy (about 4 MeV) as well as the high-energy (30 MeV) protons. In the largest events protons were observed up to energies of about 100 MeV. The shocks were rather fast and in some cases extended to more than 90% east of the flare site. Assuming a symmetrical configuration, this would correspond to a total angular extent of some interplanetary shocks of about 180%. In addition, due to the use of three spacecraft at different locations we find some indication for the shape of the shock front: the shocks are fastest close to the flare normal and are slower at the eastern flank. For particle acceleration we find that close to the flare normal the shock is most effective in accelerating energetic particles. This efficiency decreases for observers connected to the eastern flank of the shock. In this case, the efficiency of shock acceleration for high-energy protons decreases faster than for low-energy protons. Observation of the time-intensity profiles combined with variations of the anisotropy and of the steepness of the proton spectrum allows one in general to define two components of an event which we term ‘solar’ and ‘interplanetary’. We attempt to describe the results in terms of a radially variable efficiency of shock acceleration. Under the assumption that the shock is responsible not only for the interplanetary, but also for the solar component, we find evidence for a very efficient particle acceleration while the shock is still close to the Sun, e.g., in the corona. In addition, we discuss this series of strong flares and interplanetary shocks as a possible source for the formation of a superevent.

Multi-spacecraft observations by Helios, IMP, and Venera show that interplanetary shocks can extend up to more than 90° east of the flare normal and are capable of accelerating particles, in particular protons up to energies of some tens of MeV. At the flanks the shock speed and the acceleration efficiency decrease; this decrease is more pronounced in high than in low energy protons. Shock spikes can be observed at energies up to 50 MeV and shock acceleration seems to be very effective inside 0.5 AU.

Solar energetic particle events often consist of two components: a ‘prompt’ component of particles accelerated in the flare or by a coronal shock, and an ‘energetic storm particle’ component accelerated by an interplanetary shock. In events observed by two or more spacecraft the time-development of the proton spectrum, together with the analysis of the intensity and anisotropy time profiles, allows one to distinguish between these components.

From the viewpoint of large particle events, in particular large impulsive events that can be observed at angular distances up to 100° from the flare site, we re-examine the role of interplanetary and coronal shocks for the acceleration and propagation of energetic particles. Special attention is paid to events observed by two or more spaceprobes because the observations at different locations in space allow additional clues, as e.g. a more direct observation of the longitude range over which particles can be accelerated and injected, and helps to make the analysis less sensitive against peculiarities of individual events. We will give evidence for a prompt component (particles accelerated on the sun) in gradual events observed at large angular distances by means of the analysis of the time-development of the proton spectrum as well as by comparison of events observed at different longitudinal distances from the flare. The long time scales for the propagation of interplanetary shocks compared to the much earlier particle injection support this separation in prompt and shock-accelerated particles. Coronal shocks as an alternative mechanism for azimuthal transport for the prompt component and the particles in impulsive flares will be discussed. These observations will allow us to formulate some questions on shock acceleration and propagation.

Mean free paths of solar energetic protons are derived from a power spectral analysis of the magnetic field fluctuations during the time of solar particle events observed on board Helios 1 and 2 in the inner heliosphere by applying quasilinear theory (QLT) under the slab model assumption. For the same events mean free paths are also derived from an analysis of the observed particle time-intensity and time-anisotropy profiles. A comparison of the results from the two approaches reveals that the large discrepancy of a factor of ten between fit and QLT mean free paths, which is commonly cited in the literature, does not appear for a number of events and that the discrepancy, expressed as the ratio of the mean free paths from the particle analysis and from quasilinear theory, can have any size between 0.5 and about 25 for different events for 18.5 MeV protons. This situation implies new requirements for theoretical approaches that attempt to solve the discrepancy problem.

Energetic particle increases in the energy range 4 to 130 MeV observed by the Kiel Electron Telescope (KET) during the in-ecliptic part of the ULYSSES mission between 1 and 5.4 AU differ distinctly from their appearance in the inner heliosphere inside 1 AU. Prompt events are rare, and for most of the events velocity dispersion is lacking. The observed intensity-time profiles show poor time relations with optical solar flares. The data is far better organized by the structure of the interplanetary medium with its shocks, tangential discontinuities, corotating interaction regions, heliospheric current sheet crossings (sector boundaries), and coronal mass ejections. Nine particle events are discussed in detail. Spectral information as well as composition measurements are used to determine the source of the particle increases: solar, interplanetary, and Jovian. The few prompt events can be fitted with diffusive interplanetary propagation models, yielding radial mean free paths in the range λ r = 0.05 to 0.15 AU. The shock related events are dominant at these intermediate distances, with particularly high intensities of MeV-electrons and > 30 MeV protons at merged or double shocks. A new feature are slowly-varying populations (SVP) with long time scales neither related to prompt events nor to local shock effects.

We discuss properties of solar energetic particle (SEP) events observed by both Helios spacecraft in the time period March 1976 to March 1980, in particular variations of the intensity time profiles with angular distance between the flare and the observer's magnetic footpoint. Special attention is paid to the neutral lines of the large-scale coronal magnetic field. For individual events we will show that sector boundaries can have a strong influence on intensities and time-scales of SEP events. This can be seen best in events in which both spacecraft are connected more or less symmetrically around the flare site with a sector boundary between them. In a statistical approach we discuss variations of onset and maximum times as well as maximum intensities with angular distance between the flare and the observer's magnetic footpoint for 39 SEP events. The use of two spaceprobes has the advantage that unknown flare parameters, such as the number of injected particles and the time of acceleration, can be eliminated by studying only relative variations of time and intensity with angular distance. These variations were analyzed under consideration of the sector boundaries of the large-scale coronal magnetic field. We find (1) particles can be observed on both sides of sector boundaries during both, impulsive and gradual, events, (2) the onset times of ∼0.5-MeV electrons can be ordered by the occurrence of sector boundaries, inside the flare sector we can define some kind of “azimuthal propagation velocity” Δϕ/Δtons with ≥4°/min, outside the flare sector this velocity is ≤1°/min, (3) the azimuthal propagation of ∼20-MeV protons seems to be systematically slower, (4) there seems to be no difference in the variations of onset times or maximum intensities with angular distance between impulsive and gradual events, and (5) within the broad scatter the variation of the maximum intensity with angular distance is not systematically influenced by the crossing of sector boundaries, despite the obvious influence of sector boundary crossings in individual events. These observations support the association of the fast propagation region (FPR) with the large-scale polarity cells of the coronal magnetic field. The “transport” inside the FPR can be understood in terms of an open cone of propagation. The “transport” outside the FPR can be interpreted in terms of a propagation mechanism or acceleration at a shock.

[1] Precipitating solar protons contribute to ozone depletion in the atmosphere; α particles and electrons also precipitate during solar energetic particle (SEP) events. If the SEP is accompanied by a shock, then magnetospheric particles can also be injected into the atmosphere as the shock hits the magnetosphere. Both particle species in both particle populations show distinct energy spectra (and thus penetration depth in the atmosphere) and precipitate in different regions: the SEP inside the polar cap and the magnetospheric particles inside the auroral oval. In this paper, we reevaluate the 3-D spatial and temporal precipitation patterns of these particle populations for the October–November 2003 event and compare the results to conventional approaches using only protons in evaluating SEP consequences. The main results are as follows: (1) The 3-D model AIMOS gives a very differentiated picture of the global ionization maps; (2) if only protons are considered, the differences between the 3-D model and the conventional approach of homogeneous precipitation inside the polar cap are small in NOx production and ozone depletion in the mesosphere and stratosphere; and (3) the consideration of electrons in addition to protons leads to significant increases in atmospheric ionization in the mesosphere, less so in the stratosphere. This is reflected in changes in the chemical composition as shown here for ozone depletion and an increase of NOx.

For the time periods 1979 April 22–May 17 and 1980 May 9–June 10, when the HELIOS spacecraft were located inside 0.5 AU, we compared the antenna temperature TA of the 466 kHz type III bursts measured by the SBH instrument on ISEE 3 with the fluxes of ∼ 0.5 MeV electrons measured by HELIOS. For 51 flare-associated kilometric type III bursts (FAIII bursts) with log(TA) > 10 we find: (1) 25 bursts (49%) are accompanied by a relativistic electron event in interplanetary space, (2) the probability for detection of an electron event decreases from more than 74% inside a cone of ± 20 ° to 56% inside a cone of ± 60° around the flare site, (3) there is only a small correlation between the brightness temperature of the radio burst and the size of the electron event, and (4) despite the broad scatter of these values there is a clear indication that for a given size of the relativistic electron event the intensity of the type III burst is about a factor of 5 higher if it is accompanied by a type II burst. These results give evidence (a) that at least part of the relativistic electrons frequently is accelerated together with non-relativistic electrons and (b) that the coronal shock associated with the metric type II burst has a weaker effect on relativistic than on non-relativistic electrons.

We present observations of solar energetic particles and shock-accelerated particles observed by the Kiel Electron Telescope (KET) on board the Ulysses spacecraft in the time interval 26 October 1990 to mid November 1991. Prompt events with diffusive propagation were observed mainly at small radial distances while at larger distances shock-related events became dominant. Particularly high intensities of high energy electrons and >30 MeV/n nuclei are observed at merged or double shocks. Slowly-varying populations (SVP) with long time scales neither related to prompt events nor to local shock effects are a new feature at these intermediate distances.

[1] We present a 3-D numerical model of atmospheric ionization due to precipitating particles with high spatial resolution. The Atmospheric Ionization Model Osnabruck (AIMOS) consists of two parts: a GEANT4-based Monte Carlo simulation and a sorting algorithm to assign observations from two polar-orbiting satellites to horizontal precipitation cells, depending on geomagnetic activity. The main results are as follows: (1) the sorting algorithm and thus the 3-D mapping of particle fluxes works reasonably well; (2) ionization rates are in good agreement with the ones from earlier models; (3) during quiet times, the major contribution to ionospheric ionization is from electrons both in the polar cap (solar electrons) as well as in the auroral oval (magnetospheric electrons) with the ionization in the auroral oval exceeding that in the polar cap; (4) during solar particle events the dominant effect in the polar cap in the stratosphere and mesosphere is from solar protons although solar electrons can contribute up to 30% to the ionization; (5) during strong shocks following a solar particle event, in the auroral oval magnetospheric electrons and protons lead to ionization rates of up to some 10% of the ones of solar particles; and (6) independent of particle source and precipitation site, in general, ionization by electrons is more important in the thermosphere.

[1] For the large solar proton event of July 2000, the Halogen Occultation Experiment instrument observed a short-term decrease of mesospheric HCl in the northern polar region. Atmospheric chemistry and ion chemistry simulations show that HCl is converted into active chlorine species (ClO, Cl, and HOCl). Two main processes drive the transformation of HCl into active chlorine: reactions of negative chlorine species directly increase the concentrations of uncharged active chlorine compounds at the expense of HCl and the production of reactive O(1D) through N(2D) + O2 → O(3P, 1D) + NO has a considerable impact on the neutral chlorine chemistry.

[1] Strength and structure of the Earth’s magnetic field control the deflection of energetic charged particles of solar and cosmic origin. Therefore variations of the geomagnetic field occurring on geological timescales affect the penetration of charged particles into the atmosphere. During solar proton events (SPEs) the flux of high-energy protons from the Sun is markedly increased. In order to investigate the impact of SPEs on the middle atmospheric ozone on longer timescales, two-dimensional atmospheric chemistry and transport simulations have been performed using simulated time series of SPEs covering 200 years. Monte Carlo calculations were used to obtain ionization rates, which were then applied to the atmosphere under the consideration of different shielding properties of the geomagnetic field. The present-day magnetic field configuration and four other scenarios were analyzed. For the first time, field configurations representing possible realistic situations during reversals have been investigated with respect to SPE-caused ozone losses. With decreasing magnetic field strength the impacts on the ozone are found to significantly increase especially in the Southern Hemisphere, and subsequently, the flux of harmful ultraviolet radiation increases at the Earth’s surface. The ozone destructions are most pronounced in the polar regions, and for some field configurations they exceed the values of ozone hole situations after large SPEs. In contrast to ozone holes the depletions due to SPEs are not restricted to winter and spring times but persist into polar summer.

[1] The Earth’s magnetosphere acts as a shield against highly energetic particles of cosmic and solar origin. On geological timescales, variations of the internal geomagnetic field can drastically alter the magnetospheric structure and dynamics. This paper deals with energetic particles in the paleomagnetosphere. Scaling relations for cutoff energies and differential particle fluxes during periods of reduced dipole moment are derived. Particular attention is paid to high rigidity galactic cosmic ray particles in the GV range and to lower rigidity solar energetic particles. We find that in the paleomagnetosphere of a strongly reduced dipole moment, solar protons of several tens of MeV may access the Earth’s atmosphere even at midlatitudes. Higher-order core-field components can widen the polar caps and open new particle-entry regions around the equator. Potential field modeling of the paleomagnetosphere and magnetohydrodynamic (MHD) simulations are utilized to study the impact of solar particles on the Earth’s atmosphere for more complex field configurations that are likely to occur during geomagnetic polarity transitions.

[1] A possible connection between the January 2005 solar proton events (SPEs) and the partial disappearance of Noctilucent clouds (NLCs) in the southern polar mesopause region is studied. Space-borne measurements of the NLC occurrence rate made with SCIAMACHY on Envisat as well as temperature measurements with MLS on Aura are employed. Immediately after the onset of the enhanced solar particle precipitation on January 16, 2005, we observe a severe decrease in the NLC occurrence rate. Between 70°S–80°S the NLC occurrence rate drops from about 80% to less than 20% within the period of enhanced solar proton fluxes. Throughout this period an anti-correlation between NLC occurrence rate and temperatures at NLC altitude is found, and the disappearance of NLCs is apparently caused by increasing temperatures. Potential mechanisms leading to the warming are discussed.

[1] We use atmospheric ozone density profiles between 35 and 65 km altitude derived from SCIAMACHY limb measurements to quantify the ozone changes caused by the solar proton events from 26 October to 6 November 2003, known as the “Halloween storm.” Detailed maps and daily resolved time series up to 5 weeks after the first event are compared with the results from a chemistry, transport, and photolysis model of the middle atmosphere that includes NOx and HOx production due to energetic particle precipitation. The general features of the ozone loss are captured by the model fairly well. A strong ozone depletion of more than 50% even deep into the stratosphere is observed at high geomagnetic latitudes in the Northern Hemisphere, whereas the observed ozone depletion in the more sunlit Southern Hemisphere is much weaker. Reasons for these interhemispheric differences are given. Two regimes can be distinguished, one above about 50 km dominated by HOx (H, OH, HO2) driven ozone loss, one below about 50 km, dominated by NOx (NO, NO2) driven ozone loss. The regimes display a different temporal evolution of ozone depletion and recovery. We observe for the first time an establishment of two contemporaneous maxima of ozone depletion at different altitudes, which solely can be explained by these regimes.

Space physics is the application of physical concepts to a complex and highly variable system of environments: the Sun, the interplanetary medium, the planets, and the interactions between them. Space physics is therefore different from laboratory physics — it asks different questions, uses other methods, and builds models on a different basis. In other words, space physics has a different view of a physical system from that which laboratory physics has. This last chapter is not meant as a comprehensive overview of scientific methodology or philosophy. Instead, it just gives hints about some of the methods of space physics which might be worth to be evaluated a little bit further. Thus this chapter is meant to help one think about the facts of space physics as presented in the other chapters, as well as to think about thinking.

A magnetosphere is shaped by the interaction between a planetary magnetic field and the solar wind. The magnetopause is a discontinuity separating both fields, forming a cavity in the solar wind. Since the solar wind is a supersonic flow, a standing shock wave, the bow shock, develops in front of the magnetopause. In the anti-sunward direction, the magnetosphere is stretched by the solar wind, forming the magnetotail. Inside the magnetosphere, different plasma regimes exist, dominated by ionospheric plasma in the plasmasphere, a highly variable mixture of ionospheric and heliospheric plasma in the geosphere, and by the solar wind plasma in the outer magnetosphere. These different regimes are coupled by fields and currents. Inside the plasmasphere energetic particles are trapped in the radiation belts. The inner magnetosphere can be approximated as a slightly distorted dipole field. It is coupled to the ionospheric current system, with energy in the form of particles and waves exchanged between both regimes. Both ionospheric currents and the ring current associated with the radiation belts modify the dipole field.

In space physics the motion of charged particles in electric and magnetic fields can be described by a test particle approach: the particles are guided by the field but their motion does not affect the field. This approach is valid if the energy density of the magnetic field exceeds that of the particles. In the test particle approach the motion can be separated into two parts: the motion of a guiding center of the particle orbit and a gyration around it. The guiding center motion can be interpreted as the effective motion of the particle, averaged over many gyrations. This concept is applied to drifts in static electromagnetic fields. The adiabatic invariants allow simple estimates of the particle motion in temporally and spatially slowly varying fields; they are applied to the motion of particles in the Earth’s radiation belts. This chapter starts with a brief recapitulation of the basics of electromagnetic field theory.

Particles in interplanetary space come from sources as diverse as the Sun, the planets, and the vastness of space. The properties of the different particle populations provide information about the acceleration mechanism(s) and the propagation between source and observer. Thus energetic particles can also be used as probes for the properties of the interplanetary medium. To describe acceleration and propagation, we use concepts such as reconnection, acceleration at shock waves, and wave—particle interactions.

[1] During a polarity transition of the Earth’s magnetic field, the structure and strength of the field change significantly from their present values. This will alter the global pattern of charged particle precipitation into the atmosphere. Thus, particle precipitation is possible into regions that are at the moment effectively shielded by the Earth’s magnetic field. A two-dimensional global chemistry, photolysis and transport model of the atmosphere has been used to investigate how the increased particle precipitation affects the chemical composition of the middle and lower atmosphere. Ozone losses resulting from large energetic particle events are found to increase significantly, with resultant losses similar to those observed in the Antarctic ozone hole of the 1990s. This results in significant increases in surface UV-B radiation as well as changes in stratospheric temperature and circulation over a period of several months after large particle events. INDEXTERMS:0340Atmospheric Composition and Structure: Middle atmosphere—composition and chemistry; 0341 Atmospheric Composition and Structure: Middle atmosphere—constituent transport and chemistry (3334); 1535 Geomagnetism and Paleomagnetism: Reversals (process, timescale, magnetostratigraphy); 1650 Global Change: Solar variability; 2716 Magnetospheric Physics: Energetic particles, precipitating. Citation: Sinnhuber, M., J. P. Burrows, M. P. Chipperfield

Die verbleibenden beiden Kapitel werden Sie in Wahrscheinlichkeiten, Verteilungsfunktionen, Statistik und Fehlerrechnung einfuhren. Physikalische Anwendungsbereiche der Wahrscheinlichkeitstheorie sind die Bereiche, in denen keine exakten Aussagen uber Endzustande gemacht werden konnen sondern nur Wahrscheinlichkeitsaussagen uber die Mittelwerte interessierender Grosen. Das erste Beispiel, das Ihnen begegnen wird, ist die Thermodynamik und insbesondere die Maxwell’sche Geschwindigkeitsverteilung sowie die Entropie als ein Mas fur die Unbestimmtheit — oder die Diffusion, die wir bereits im vorangegangenen Kapitel betrachtet haben. Diese Begriffe werden in diesem Kapitel eingefuhrt; das folgende Kapitel fuhrt Sie auf der Basis der hier eingefuhrten Verteilungsfunktionen in Statistik, Fehler- und Ausgleichsrechnung ein. Damit wird das Handwerkszeug zur Auswertung von (Praktikums-)Versuchen bereitgestellt.