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Traditional Martian bow shock and magnetic pileup (magnetopause) boundary models are based on the fitting of free parameters in a prescribed formula. The form of the formula, fitted data, and considered controlling parameters distinguish the individual models from each other. However, all these models have one thing in common: the shape of the boundary and the parametric dependence assumed are fixed by the prescribed formula. The fitted data set typically consists of individual identified boundary crossings. This approach can suffer from a significant bias, as the boundary crossings are more likely to be identified in regions where a spacecraft spends more time. In this study, we use an automated region classification of the data measured by the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft to solar wind, magnetosheath, or magnetosphere. This is achieved by applying the Support Vector Machine method to individual spacecraft half-orbits (from periapsis to apoapsis or vice versa). Two different models of the locations of the bow shock and magnetic pileup boundaries are then constructed based on neural networks: i) a model trained using the classified data, and ii) a model trained using individual identified boundary crossings. As compared to formal empirical modeling efforts, the neural network models do not assume any prescribed shape/distance formula. Optimal model parameterization (considering the solar wind dynamic pressure, solar ionizing flux, crustal magnetic field magnitude, Alfvén Mach number, and interplanetary magnetic field magnitude) is discussed and the model performance evaluated. [ABSTRACT FROM AUTHOR]

Whistler mode quasiperiodic (QP) emissions are electromagnetic waves at frequencies between about 0.5 and 4 kHz observed in the Earth's inner magnetosphere, which are characterized by their nearly periodic time modulation of the wave intensity. Although they have been studied using both ground-based and satellite instruments for already a few decades, their origin remains unclear. Recent studies of these emissions revealed that, on top of the main modulation period, some of the events exhibit an additional fine inner intensity modulation. We use high-resolution electromagnetic wave measurements obtained by the low-altitude DEMETER spacecraft to systematically study the presence/absence of such fine inner structure and the corresponding fine inner modulation periods. Altogether, as many as 251 events are analyzed. Out of these, the clear fine inner modulation is observed for 71 events, only unclear fine inner modulation is observed for 63 events, and the fine inner modulation is completely absent for 117 events. We show that the fine inner structure tends to occur primarily for QP events with shorter modulation periods. The fine inner modulation periods are on the order of few seconds, corresponding to bounce times of whistler mode waves in between the hemispheres. They typically stay quite constant within a single event, and they tend to be lower at larger geomagnetic latitudes (L-shells). Interestingly, the fine inner modulation periods are positively correlated with the main QP modulation periods. The results obtained are of interest for understanding possible mechanisms responsible for the generation of QP events. [ABSTRACT FROM AUTHOR]

Very low frequency wave intensity variations measured by the Kannuslehto station, Finland in the frequency range 0–12 kHz between 2016 and 2020 are analyzed by the principal component analysis (PCA). As the analyzed ground-based measurements are basically continuous, the length of individual basis vectors entering into PCA is fundamentally arbitrary. To better characterize both long- and short-period variations, two PCAs with different lengths of the basis vectors are eventually performed. Specifically, either daily frequency–time spectrograms or individual frequency spectra are chosen as the PCA basis vectors. Analysis of the first three principal components shows substantial variations of the wave intensity due to seasonal and local time effects. Intensity variations related to the geomagnetic activity characterized by Kp and AE indices and standard deviation of the magnetic field magnitude are less significant. Moreover, PCA allows one to distinguish between nighttime and daytime Kannuslehto variations and study them independently. Solar and geomagnetic activity effects on the daytime and nighttime measurements are discussed. Wave intensity variations related to substorm occurrence are also analyzed. [ABSTRACT FROM AUTHOR]

The Martian ionosphere originates from the ionization of the planetary neutral atmosphere by solar radiation. This conductive layer is embedded within the thermosphere and exosphere of Mars where it forms a highly variable interaction region with the solar wind. The Martian ionosphere has been continuously observed by the three plasma instruments MaRS, MARSIS and ASPERA-3 on Mars Express for the last 20 years (>10 Martian years). Those long-term observations laid a solid foundation for what we know today about the Martian ionosphere, and provided numerous opportunities for collaboration and coordinated observations with other missions. This review describes the most significant achievements of Mars Express for the ionosphere, such as the dynamics and structures of both day and nightside, its variability and couplings with the lower atmosphere, as well as the improvement of atmospheric and ionosphere modelling. Mars Express has also provided a better characterization of the role of several external and internal drivers in controlling the ionosphere, such as the Martian crustal magnetic fields, solar activity, seasons, dust lifting from the surface, and even the direct interaction of the Martian ionosphere with the coma of an Oort-cloud comet (C/2013 A1, Siding Spring). [ABSTRACT FROM AUTHOR]

Very low frequency (VLF) emissions of natural origin were identified for the first time by analyzing 1‐hr ground‐based magnetic field spectrograms in the 0.2‐ to 39‐kHz frequency range. Data were used from the Kannuslehto radio receiver (L‐shell ~5.5), recorded during different campaigns between 2006 and 2019. The spectrograms exhibit banded structures, which consist of several strip elements that vary in time and frequency over the event duration. Statistical analysis of 95 events shows that they are observed in the frequency range that extends from 2 to ~37 kHz, and mainly appearing above 16 kHz. The events span from 4 to 110 min and occur in the evening sector (~17–01 magnetic local time), mostly during quiet geomagnetic conditions. Furthermore, they are primarily left‐handed polarized and are associated with bursts of lightning‐related radio emissions such as sferics and tweeks. Plain Language Summary: Advances in modern technology have created tangible scientific and societal benefits, allowing us to make new discoveries, perform better observations, and monitor important parameters of our Earth's condition. In this study, new digital processing tools are used to uncover a natural, namely, non–man‐made, very low frequency (VLF) radio wave emission never observed before. These emissions consist of several strips as appear on our detector screens, with structures having frequency drifts that vary during the event duration. Moreover, the range of frequencies in which these emissions are observed, 16–39 kHz, is higher than the typical one used for VLF observations. The measurements were made in Northern Finland during different campaigns, between 2006 and 2019, using ~10‐m size square‐loop radio antennas installed on the ground. The duration of the structured emissions ranges from about four to a hundred minutes. These emissions occur during evening and early night hours, and when the Earth's magnetic conditions are calm. Additionally, we learned that the field perpendicular to the wave propagation rotates clockwise when looking at the incoming wave. A remarkable characteristic of these emissions is that they are coincidental in time with the occurrence of bursts of lightning VLF emissions. Key Points: VLF emissions at frequencies 16–39 kHz with dominant left‐handed polarization are identified in ground‐based measurementsThese emissions exhibit a clear banded structure, and they occur during dusk‐to‐night local time sectorSome of their features resemble those of banded structure in auroral hiss, while others imply links to propagation of lightning sferics [ABSTRACT FROM AUTHOR]

Each enterprise contemplates the ways of saving. The warehouse is one of the tools that helps in optimizing company costs and that also forms an integral part of the transformation process at the same time. It allows one to bridge the mismatch between the transfer of goods and materials between a producer and a consumer. Selecting the correct type of warehouse can affect not only the cost items, but it can also affect the delivery time of the required goods or materials which the end customer´s satisfaction depends upon. What is equally important is the role of a warehouse area location as it can affect the time required for a consignment delivery, which is also in conjunction with the right connections to the transport infrastructure. As certain analyses show, there are enough of the different types of storage facilities in various locations in Slovakia. Just such a tactical and strategic decision must take into account not only the location, the infrastructure connection or the provided services, but it must also include the financial aspects in order to achieve cost savings and the optimization of the costs.The aim of this paper is to define the current situation in the market with storage facilities in Slovakia. [ABSTRACT FROM AUTHOR]

The current tough competition prevalent within the market economy is forcing business entities to achieve efficiency in their processes. This also applies to the transfer of goods from point A to point B, which is the subject of transportation. This process is influenced by many factors. It is necessary to not only consider the time,i.e. the fact that the required goods must be delivered in time, but it is also essential to take the financial aspect linked into account, for example, with the cost items such as fuel, salaries etc. These and many other factors also influence the movement of goods within a warehouse, in which the business entity must maximize the space required for the storage of the goods, while minimizing the time necessary for the storage, and equally while optimizing the cost. The aim of this paper follows from the above, which is based on the facts of the course of storage operations in the chosen enterprise,to design an optimal layout of the storage area which should increase the efficiency of the logistical operations. [ABSTRACT FROM AUTHOR]

Observations of proton density fluctuations of the solar wind at 1 au have shown the presence of a decade-long transition region of the density spectrum above sub-ion scales, characterized by a flattening of the spectral slope. We use the proton density fluctuations data collected by the BMSW instrument on-board the Spektr-R satellite in order to delimit the plasma parameters under which the transition region can be observed. Under similar plasma conditions to those in observations, we carry out 3D compressible magnetohydrodynamics (MHD) and Hall-MHD numerical simulations and find that Hall physics is necessary to generate the transition region. The analysis of the k ω power spectrum in the Hall-MHD simulation indicates that the flattening of the density spectrum is associated with fluctuations having frequencies smaller than the ion cyclotron frequency. [ABSTRACT FROM AUTHOR]

• The paper presents the electron fluxes measured by SATRAM on the Proba-V satellite in LEO. • A neural network has been apllied for particle identification and flux estimation at low fluxes. • A new simple, statistical method is provided to estimate fluxes at high fluxes. • The fluxes are compared with the fluxes measured by EPT on the Proba-V satellite. • Good agreement has been achieved.. We present the determination of electron fluxes measured by the Space Application of Timepix Radiation Monitor (SATRAM), a pixelated single-layer particle detector and the comparison with the Energetic Particle Telescope (EPT), a science-class radiation spectrometer. Both are attached to the Proba-V satellite of the European Space Agency. SATRAM hosts a Timepix chip with a 300 μ m thick silicon sensor divided into a 256 × 256 pixel matrix with 55 μ m pixel pitch. Simulations were conducted to determine the geometric factor of the sensor and the effective area that includes the shielding effects from all directions. The simulation was further used to study the influence of secondary particle production, track interruption, and backscattering on the number of detected particles. Particle identification is performed using two different methods. The first method requires that particle tracks are individually identifiable. A neural network was developed for this purpose, achieving an accuracy of 90.2% for particle identification. If individual particle tracks could not be identified, a statistical approach was used utilizing the energy deposition, average cluster energy, and the last known fraction of electrons. A comparison of the two instruments shows good agreement within one order of magnitude for the majority of the data. [ABSTRACT FROM AUTHOR]

The Radio Occultation Science Experiment (ROSE; Withers et al., 2018, 2020) on the Mars Atmosphere and Volatile EvolutioN (MAVEN) satellite has produced over 400 electron density profiles from July 2016 to November 2019. These N e (h) profiles occurred over a large range of solar zenith angles (54o- 130o) and solar flux conditions (24–54 solar flux units at Mars). One of the goals of the MAVEN mission is to characterize the status of the topside ionosphere at Mars as a reservoir of possible escaping plasma. Here we evaluate how ROSE topside ionospheric measurements, made predominantly under solar minimum conditions, compare with the only empirical model of the topside ionosphere (Němec et al., 2019). To assess congruence between the model and the observations, a deviation factor (DF) is calculated for each predicted versus observed N e (h) profile. Diurnally, low DFs (and thus higher agreement) occur for occultations with solar zenith angles (SZA) < 82o. On a longer time scale, lower solar fluxes tend to have higher DF values. Correlations of the maximum electron density (N max) of each profile (predicted and observed) have an overall correlation coefficient (CC) of 0.96. Similarly, the observed total electron content of the topside ionosphere (TTEC) agrees with predictions (CC = 0.86). The model and the predictions differ most for the altitude of peak density (CC = 0.62 for SZA < 90o). • Topside ionosphere model from MEX validated successfully using new MAVEN data. • Good model-data agreement except for high solar zenith angles and low solar fluxes. • Solar minimum ionospheric variability at Mars greater than found at Earth. [ABSTRACT FROM AUTHOR]

Turbulent cascade transferring the free energy contained within the large scale fluctuations of the magnetic field, velocity and density into the smaller ones is probably one of the most important mechanisms responsible for heating of the solar corona and solar wind, thus the turbulent behavior of these quantities is intensively studied. The temperature is also highly fluctuating quantity but its variations are studied only rarely. There are probably two reasons, first the temperature is tensor and, second, an experimental determination of temperature variations requires knowledge of the full velocity distribution with an appropriate time resolution but such measurements are scarce. To overcome this problem, the Bright Monitor of the Solar Wind (BMSW) on board Spektr-R used the Maxwellian approximation and provided the thermal velocity with a 32 ms resolution, investigating factors influencing the temperature power spectral density shape. We discuss the question whether the temperature spectra determined from Faraday cups are real or apparent and analyze mutual relations of power spectral densities of parameters like the density, parallel and perpendicular components of the velocity and magnetic field fluctuations. Finally, we compare their spectral slopes with the slopes of the thermal velocity in both inertial and kinetic ranges and their evolution in course of solar wind expansion. [ABSTRACT FROM AUTHOR]

Quasiperiodic (QP) electromagnetic emissions are whistler mode waves at typical frequencies of a few kHz characterized by a periodic time modulation of their intensity. The DEMETER spacecraft observed events where the QP emissions exhibit a sudden change in the wave vector and Poynting vector directions. The change happens in a short interval of latitudes. We explain this behavior by ionospheric reflection and present a ray-tracing simulation which matches resulting wave vector directions. We also attempt to locate the source region of these emissions and conclude that they are most probably generated at the inner boundary of the plasmapause which also acts as a guide during the propagation of the QP emissions. [ABSTRACT FROM AUTHOR]

This paper highlights significant advances in plasmaspheric wave research with Cluster and Image observations. This leap forward was made possible thanks to the new observational capabilities of these space missions. On one hand, the multipoint view of the four Cluster satellites, a unique capability, has enabled the estimation of wave characteristics impossible to derive from single spacecraft measurements. On the other hand, the Image experiments have enabled to relate large-scale plasmaspheric density structures with wave observations and provide radio soundings of the plasmasphere with unprecedented details. After a brief introduction on Cluster and Image wave instrumentation, a series of sections, each dedicated to a specific type of plasmaspheric wave, put into context the recent advances obtained by these two revolutionary missions. [ABSTRACT FROM AUTHOR]

• Temporal changes in hydraulic properties were slower than in chemical properties. • Organic mulches increased soil organic matter content and aggregate stability. • Physical quality of soils under organic mulches was lower than for other scenarios. • Readily available water under organic mulches was lower than for other scenarios. A long-term application of various mulch materials may lead to changes in certain soil properties, which mostly remain unreviewed. Therefore, our study focused on the mulch effect on a larger group of Haplic Fluvisol properties. The experiment was performed on 27 perennial patches covered by eight different mulch materials (bark chips, wood chips, wheat straw, cardboard, paper foil, decomposable matting, nonwoven fabric covered by bark chips, and crushed basalt) and control patches without any mulch during the 4 year period. The highest daily ranges of soil temperature were found in control patches without mulch, lower temperature ranges below foils mulches, and the lowest below organic mulches. Mulches preserved water storage in soil mainly during spring before vegetation integration and after perennials' cutting. Organic carbon content (C ox), aggregate stability, and pH mostly did not show any trends over time, except for C ox and aggregate stability from patches with bark or wood chips and wheat straw. In these cases, decomposed organic matter significantly increased both properties. On the other hand, the soil hydraulic properties (mostly due to no-till practice) considerably changed in all patches. The saturated and residual water contents, saturated hydraulic conductivity, and reciprocal of the air-entry pressure head increased. Correspondingly, the bulk density decreased. Soil water retention curves from the patches with bark or wood chips were more gradual than those from other patches, which indicates higher water retention capacity for lower pressure heads. However, the physical quality of soils under organic mulches expressed by the slope at the retention curve inflection point was lower than that for other scenarios. Readily available water under organic mulches was also lower than that for other setups. This suggests that organic mulches have largest impacts on soil conditions, which can be either favourable or adverse. [ABSTRACT FROM AUTHOR]

At Mars, the solar wind interacts directly with the planet&#x2019;s extended atmosphereand ionosphere to form an induced magnetic barrier that deflects the solar windaround the planet. Through this interaction, the solar wind deposits energy andmomentum into the ionosphere resulting in plasma heating, acceleration, and escape.Consequently, the global structure and dynamics of the ionosphere are thought to be affectedby the conditions that prevail in the upstream solar wind. Observational studiesdetailing these effects, however, have been limited owing to the lack of concurrentobservations of the ionosphere and upstream solar wind. We present results from astatistical analysis in which we studied these effects using ionospheric electron densitymeasurements from the MARSIS (Mars Advanced Radar for Subsurface and IonosphereSounding) Radar on Mars Express, and upstream solar wind measurements frominstruments on MAVEN (Mars Atmosphere and Volatile EvolutioN). Our resultsshow that, during times of high solar wind dynamic pressure, the plasma scaleheight in the topside ionosphere is reduced and electron densities in the nightsideionosphere are enhanced. The analysis also reveals that there is an asymmetry in theionosphere with respect to the direction of the solar wind -V × B motional electric field. [ABSTRACT FROM AUTHOR]