Search

The space physics community continues to grow and become both more interdisciplinary and more intertwined with commercial and government operations. This has created a need for a framework to easily identify what projects can be used for specific applications and how close the tool is to routine autonomous or on-demand implementation and operation. We propose the Application Usability Level (AUL) framework and publicizing AULs to help the community quantify the progress of successful applications, metrics, and validation efforts. This framework will also aid the scientific community by supplying the type of information needed to build off of previously published work and publicizing the applications and requirements needed by the user communities. In this paper, we define the AUL framework, outline the milestones required for progression to higher AULs, and provide example projects utilizing the AUL framework. This work has been completed as part of the activities of the Assessment of Understanding and Quantifying Progress working group which is part of the International Forum for Space Weather Capabilities Assessment.

We perform a statistical study of 3-s ultra-low frequency (ULF) waves using Magnetospheric Multiscale observations in the Earth's foreshock region. The average phase velocity in the plasma rest frame is determined to be anti-sunward, and the intrinsic polarization is right-handed. We further examine the linear instability conditions based on the drift-bi-Maxwellian distribution functions according to the observed plasma conditions. The resulting instability is a solution to the common dispersion equation of the ion/ion right-hand non-resonant and left-hand resonant instabilities. The predicted wave propagation is also predominantly anti-sunward. The cyclotron resonant conditions of the solar wind and backstreaming beam ions are evaluated, and we find that, in some cases, the anti-sunward propagating waves can be resonant with beam ions, which was overlooked in previous studies. The study suggests that the dispersion equation provides the 3-s ULF waves a fundamental explanation that unifies a rich variety of resonant conditions. [ABSTRACT FROM AUTHOR]

Solitary magnetic structures known as SLAMS (short large‐amplitude magnetic structures) have been considered as essential elements of collisionless shocks with quasi‐parallel geometries. Yet the physics underlying their formation remains an open question. In this paper, we use measurements from the magnetospheric multiscale mission combined with fully kinetic simulations to study the formation of SLAMS. We find that gyro‐resonance between solar wind ions and right‐hand circularly polarized electromagnetic waves results in magnetic field amplification. Gyro‐trapping by the growing magnetic field buildup the plasma density that further enhances the current and field. The solitary nature of SLAMS stems from a beat‐like magnetic field envelope where the maximum sets the initial location for nonlinear growth. Our results present a conceptual advance on SLAMS, and may shed new light on the open question of magnetic field amplification at astrophysical shocks. Plain Language Summary: We integrate MMS measurements and fully kinetic simulations to investigate the nonlinear processes underlying ultra‐low‐frequency wave growth and evolution into solitary magnetic structures known as SLAMS. The understanding gained here presents a conceptual advance on the formation of SLAMS at planetary bow shocks, and may serve as new insight into how magnetic fields in the interstellar medium are amplified to create an environment for cosmic ray production at astrophysical shocks. Key Points: Gyro‐resonance between solar wind ions and right‐hand circularly polarized electromagnetic waves results in magnetic field amplificationGyro‐trapping by the growing magnetic field buildup the plasma density that further enhances the field growthThe solitary nature of SLAMS stems from the magnetic field envelope where the maximum sets the initial locations for nonlinear growth [ABSTRACT FROM AUTHOR]

The nature of the 3‐s ultralow frequency (ULF) wave in the Earth's foreshock region and the associated wave‐particle interaction are not yet well understood. We investigate the 3‐s ULF waves using Magnetospheric Multiscale (MMS) observations. By combining the plasma rest frame wave properties obtained from multiple methods with the instability analysis based on the velocity distribution in the linear wave stage, the ULF wave is determined to be due to the ion/ion nonresonant mode instability. The interaction between the wave and ions is analyzed using the phase relationship between the transverse wave fields and ion velocities and using the longitudinal momentum equation. During the stage when ULF waves have sinusoidal waveforms up to |dB|/|B0| ~ 3, where dB is the wave magnetic field and B0 is the background magnetic field, the wave electric fields perpendicular to B0 do negative work to solar wind ions; along B0, a longitudinal electric field develops, but the V × B force is stronger and leads to solar wind ion deceleration. During the same wave stage, the backstreaming beam ions gain energy from the transverse wave fields and get deceleration along B0 by the longitudinal electric field. The ULF wave leads to electron heating, preferentially in the direction perpendicular to the local magnetic field. Secondary waves are generated within the ULF waveforms, including whistler waves near half of the electron cyclotron frequency, high‐frequency electrostatic waves, and magnetosonic whistler waves. The work improves the understanding of the nature of 3‐s ULF waves and the associated wave‐particle interaction. Key Points: A 3‐s ULF wave event observed by MMS in a foreshock region is determined to be due to the nonresonant ion beam instabilitySolar wind ions lose energies to the transverse wave field and are decelerated along the background magnetic field by the Lorentz forceThe ULF wave leads to electron heating and excites secondary waves [ABSTRACT FROM AUTHOR]

A high‐frequency spectral feature is identified in ground‐based spectrograph data at 15–30 MHz. The feature, likely of terrestrial origin, is often recorded by a group of citizen scientists (the Spectrograph User Group) whose main interest is to observe Jupiter's radio emissions. The feature appears as radio band noise enhancement in which the frequency of enhancement increases and then decreases with time, forming a "triangular spectral feature." The teepee tent shape leads to its name (TP for short). TPs usually have well‐defined leading and trailing edges. While some TPs occur in isolation, they are often seen in groups, distributed either in time or in apex frequency. While most TPs appear diffuse, close‐up views of a few TPs reveal that they actually consist of discrete bursts, highly suggestive of lightning strokes as possible radiation sources. Here, we investigate the possible generation of TPs by ionospheric reflection of radiation from remote lightning storms. Key Points: A new radio signature of terrestrial origin is identifiedThe new feature is likely produced by ionospheric reflection of HF waves from lightning storms moving relative to the observing pointThe new radio signatures may be used to detect remote lightning storms and study the ionosphere [ABSTRACT FROM AUTHOR]

The Space Physics Archive Search and Extract Consortium has developed and implemented the SPASE Data Model that provides a common language for registering a wide range of Heliophysics data and other products. The Data Model enables discovery and access tools such that any researcher can obtain data easily, thereby facilitating research, including on space weather. The Data Model includes descriptions of Simulation Models and Numerical Output, pioneered by the Integrated Medium for Planetary Exploration (IMPEx) group in Europe, and subsequently adopted by the Community Coordinated Modeling Center (CCMC). The SPASE group intends to register all relevant Heliophysics data resources, including space‐, ground‐, and model‐based. Substantial progress has been made, especially for space‐based observational data and associated observatories, instruments, and display data. Legacy product registrations and access go back more than 50 years. Real‐time data will be included. The National Aeronautics and Space Administration (NASA) portion of the SPASE group has funding that assures continuity in the upkeep of the Data Model and aids with adding new products. Tools are being developed for making and editing data descriptions. Digital Object Identifiers (DOIs) for Data Products can now be included in the descriptions. The data access that SPASE facilitates is becoming more uniform, and work is progressing on Web Service access via a standard Application Programming Interface. The SPASE Data Model is stable; changes over the past 9 years were additions of terms and capabilities that are backward compatible. This paper provides a summary of the history, structure, use, and future of the SPASE Data Model. Plain Language Summary: The Heliophysics research community requires a wide variety of data from many disparate sources in order to make substantial progress. This is especially true for space weather, where a range of data and models may be relevant to any given study. The SPASE Data Model" unifies descriptions of data from observatories or simulation models using the same language to describe all products. This streamlines finding, accessing, and using the underlying variegated files, thus speeding up and improving research. This paper gives an overview of the history, structure, and use of the SPASE Data Model and gives an idea of current directions in its development. Key Points: The Heliophysics/Space Weather community has developed a general means to register, discover, access, and use data sets and other productsThe key for ease‐of‐use is the adoption of standards for data formats, metadata, and access methodsThe Space Physics Archive Search and Extract Data Model provides a stable and general standard for the requisite metadata descriptions [ABSTRACT FROM AUTHOR]

Selected original analog telemetry tapes from three of the topside‐sounder satellites of the International Satellites for Ionospheric Studies (ISIS) program, namely Alouette 2, ISIS I, and ISIS II, were used in an earlier project to produce more than ½ million digital topside ionograms; the resulting digital topside ionograms from ISIS II were used to produce more than 86,000 globally distributed vertical topside ionospheric electron density profiles Ne(h) that cover a time span of more than a solar cycle. These Ne(h) were produced using the Topside Ionogram Scaler with True height algorithm auto‐scaling software. Before attempting to automatically process Alouette‐2 or ISIS‐I ionograms, a data‐enhancement project was initiated so as to increase the number of ionograms suitable for manual scaling and to increase the auto‐processing success rate. These enhancements were mainly to correct problems that often occurred during the analog‐to‐digital conversion of the original telemetry tapes. Here we illustrate the improvements made to the ISIS‐I digital topside ionograms and compare Ne values at the satellite altitude and Ne(h) profiles, based on the manual scaling of selected ionograms, to both the auto‐scaled values and the predictions of the International Reference Ionosphere 2016 model. The results indicate the need to improve the available auto‐processing software for the new ISIS‐I digital ionograms and that International Reference Ionosphere 2016 predicts midlatitude winter topside Ne values that are too high in the late morning and at noon but too low in the early morning. Plain Language Summary: Data from the Alouette/ISIS topside‐sounder satellites from the 1960s and 1970s still provide some of the most useful information on the topside ionosphere on a global scale. This region, that is, above the electron density peak near 300‐km altitude, is not very well represented by ionospheric models, yet it has a significant impact on advanced technological systems, such as navigation, that depend on radio signals that traverse the entire ionosphere. This study builds on earlier investigations and uses the latest digital files from the International Satellites for Ionospheric Studies‐I satellite to demonstrate the importance of these files, the challenges encountered in developing software to automatically process them, and to indicate regions where the International Reference Ionosphere model is in need of improvement. Key Points: ISIS‐1 digital topside ionogram database enhancements enable more efficient manual scaling and automatic processingManual scaling indicates the need for improvements in existing automatic‐processing software for ISIS‐1 digital topside ionogramsThe new ISIS‐1 ionograms are valuable for improving the International Reference Ionosphere model in the topside ionosphere [ABSTRACT FROM AUTHOR]

The study of Earth’s radiation belts is one of the oldest subjects in space physics. Despite the tremendous progress made in the last four decades, we still lack a complete understanding of the radiation belts in terms of their configurations, dynamics, and detailed physical accounts of their sources and sinks. The static nature of early empirical trapped radiation models, for examples, the NASA AP-8 and AE-8 models, renders those models inappropriate for predicting short-term radiation belt behaviors associated with geomagnetic storms and substorms. Due to incomplete data coverage, these models are also inaccurate at low altitudes (e.g., <1000 km) where many robotic and human space flights occur. The availability of radiation data from modern space missions and advancement in physical modeling and data management techniques have now allowed the development of new empirical and physical radiation belt models. In this paper, we will review the status of modern radiation belt modeling. [Copyright &y& Elsevier]