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32nd International Union of Radio Science General Assembly & Scientific Symposium * Montreal, Canada * 19-27 August 2017 Home Page

Scientific Program - Commission H

Commission H Chair:
Prof. Ondrej Santolik;

Commission H - Tutorial

Craig Rodger - "Drivers, Detection, and Wider Significance of Precipitation from the Radiation Belts"

Convener: O. Santolik

Wave particle interactions are a fundamental physical mechanism driving change in the Van Allen radiation belts. Growing evidence indicates that cyclotron resonance between VLF whistler-mode waves and energetic electrons play crucial roles for the acceleration of electrons to relativistic energies. It has long been recognised that the same resonances also pitch-angle scatter electrons, moving them towards the loss cone and causing loss of these electrons into the atmosphere through precipitation. Particle precipitation into the atmosphere is believed to be one significant mechanism for the loss of energetic electrons from the radiation belts. Wave-particle interactions involving ULF through to VLF waves are understood to be the most important drivers of these loss events. The majority of these waves are naturally generated, but manmade waves from large communications transmitters can also play a role, particularly in the inner radiation belt. There is growing interest in energetic electron precipitation (EEP). This is partially because of the need to include both acceleration and loss processes in radiation belt predictive models. There is also a new focus on the impact of the energetic electron precipitation on the polar atmosphere, with increasing evidence of significant changes in upper-atmospheric chemistry, and coupling to polar-surface climate. In this talk I will provide an overview of the fundamental processes driving precipitation, discuss the properties of observed EEP, and discuss its wider significance to the Earth's system. I will also attempt to include some open questions in this area.

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Commission H - "Macro/Micro-Scale Kinetic Processes at Natural Boundary Layers in Terrestrial and Planetary Environments"

Conveners: B. Lembège, I. Shinohara and G. Lakhina

Intricate microscopic/macroscopic processes take place over micro/meso/macro-scales. at natural boundary layers. These layers play a important role in the energy and momentum transfer between the solar wind and the planetary magnetosphere and/or between different regions within the magnetosphere itself. These processes are based on various wave-particle interactions, nonlinear effects and nonstationary mechanisms, which control the overall dynamics of these frontiers. The present session welcomes the discussion of recent results issued from theory, mono/multi-dimensional numerical simulations and experimental data obtained from various space missions. The comparison between these approaches is possible thanks to refined measurements obtained on board of recent multi-spacecraft missions (e.g., Cluster, Themis) and to improved simulations. Comparison with data issued from other missions (Geotail, Wind, Double Star etc) are also encouraged. Applications include magnetospheric, ionospheric and space plasma physics. Examples of boundary layers include: (i) collisionless shocks, (ii) the magnetopause, (iii) plasma sheet currents, (iv) nearby/far magnetotail dynamics (including substorms), (v) plasmapause, (vi) potential drops in the ionosphere and cusp dynamics, (vii) basic particle acceleration processes, and (viii) dynamics of interfaces in active space experiments. Any contributions related to these topics are very welcome. Comparative analysis of results dedicated to terrestrial and planetary environments are also strongly encouraged, in order to approach a more synthetic view of their understanding.

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Commission H - "Remote Sensing and Modeling of the Earth's Plasmasphere and Plasmapause"

Conveners: A. M. Jorgensen, V. Pierrard, B. Heilig

The plasmasphere is a dynamic system consisting of cold dense plasma controlled by solar activity and coupled by electromagnetic fields, currents and particle fluxes to the ionosphere and atmosphere. The plasmasphere also plays an important role in Earth's space weather. Plasma density and plasma density gradients are key parameters in wave-particle interactions in the radiation belts. Information about the plasma density distribution is now always known with sufficient spatial and temporal resolution so determine the wave power, which is a major contributor to radiation belt particle acceleration and loss. Recent advances in modeling the plasmasphere, including physics based, empirical and data assimilative approaches, improve our understanding on the dynamics of this region. These modeling efforts are based on ground based as well as in-situ measurements. Opportunities for ground-based remote sensing have grown rapidly with the deployment of many instrument arrays, while in situ observations are facilitated through multi-satellite missions. This session invites presentations on modeling and observations of the plasmasphere. Especially welcome are ground-based and space-based remote-sensing and in-situ observations, as well as new modeling and data assimilation approaches which show promise for improving understanding of plasmasphere dynamics.

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Commission H - "Wave-Particle Interactions and Their Effects on Planetary Radiation Belts"

Conveners: R. Horne, C. Kletzing, D. Shklyar

In recent years much attention has turned to the physics of the radiation belts of the Earth and other planets. New space-borne assets as well as advances in theory and simulation have led to progress in our understanding of the wave-particle physics of acceleration, loss, and transport of energetic particles in the inner magnetospheres of the planets. This session focuses on the broad range of topics of planetary radiation belts including plasmaspheres and plasmapause properties, ring current evolution, wave properties, and energetic electron and ion populations. Presentations on theory, simulation, and data studies are encouraged.

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Commission H - "Drivers, Detection, and Ionospheric Impacts of Precipitation from the Radiation Belts"

Conveners: C. Rodger, M. A. Clilverd

Particle precipitation into the atmosphere is believed to be one of the dominant mechanisms for the loss of energetic electrons from the Van Allen radiation belts, as well as losses of ring current ions. Wave-particle interactions with ULF through to VLF waves are thought to be important drivers of these loss-processes. This session is targeted at both ground-based and satellite experimental observations, as well as theoretical investigations, into the precipitation of energetic (>10 keV) to relativistic energy electrons or precipitation of ring current ions. Papers considering wave-particle interactions driving losses, measurement of loss fluxes, or the effects of this precipitation on the ionosphere are welcome. We welcome studies from existing ground, balloon or space based experiments. Note that studies directed towards radiation belt electron acceleration or transport are likely better suited to the complementary session H3.

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Commission H - "Laboratory Simulations"

Conveners: A. Fredriksen, T. A. Carter

The plasma environments surrounding the Earth and other solar system bodies display a rich variety of plasma phenomena, such as a zoo of waves and instabilities, turbulence, reconnection, particle acceleration and beam formation to mention a few. These phenomena can now be observed with unprecedented spatial and temporal resolution by modern space probes and ground-based observatories. While high-resolution observations can provide tantalizing snapshots of events and statistical overviews of dynamical behaviour, repeatable experiments under strictly controlled conditions are not possible in space. Laboratory experiments can provide useful insight in space phenomena by investigating the underlying physics under appropriately scaled, controlled plasma conditions. Among these are experimental studies of wave propagation characteristics, wave-particle interactions, and nonlinear dynamics and instabilities. Papers on basic and applied laboratory studies addressing such space plasma processes are solicited.

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Commission H - "Radio Science for Space Weather"

Conveners: M. Messerotti, V. Pierrard

Space weather perturbations are triggered by plasma processes that occur at the originating sources, e.g. magnetic reconnection causing heating, particle and plasmoid acceleration. Further plasma processes occur during propagation through the interplanetary medium, where shocks and particle beams are formed. Finally a wealth of processes occur upon interaction with planetary magnetospheres and ionospheres. All these processes are characterised by radio emissions specific to each plasma process. Hence, radio science represents a key investigative tool for space weather phenomena including triggering, propagation and interaction. Both radio physics and radio instrumentation are conceptual and, respectively, experimental tools that are needed to provide a complete analysis framework. This session is open to contributions on radio physics applied to space weather phenomena detection, characterisation, analysis and forecasting as well as to ongoing and planned projects for space- and ground-based radio studies in this field.

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Commission H - "Open Session"

Conveners: O. Santolik, J. Lichtenberger

This session solicits papers on all aspects of waves in space and laboratory plasmas that do not easily fit into other sessions within Commission H, including solar, planetary, and interplanetary plasmas, spacecraft-plasma interactions, applications to space weather, the use of space as a laboratory, spacecraft and laboratory instrumentation, and latest results from recently launched spacecraft missions and laboratory experiments.

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Commissions HG - "Active Experiments"

Conveners: V. Sonwalkar, R. Moore, N. Jackson-Booth, T. Pedersen

This session will cover recent advances in active space experiments, including ionospheric perturbations, disturbances or other effects on the space environment actively produced by high-power RF waves, chemical releases, rocket exhaust, ion engine propulsion systems or other means. In addition to presentations of observations and measurements from recent or novel experiments, theoretical and modeling developments that advance theory beyond the prevailing qualitative and descriptive state toward quantitative and predictive capabilities will also be welcomed. Topics of interest include wave generation stimulated by or propagation modified by artificial effects. Presentations on technologies, such as RF sources or chemical reactions, which may enable new or improved applications in active space experimentation, are also sought. This session will also cover the latest technical and scientific results on and concepts of space-borne radio sounding in terrestrial and extra-terrestrial ionospheres and magnetospheres including previous, current, and planned spaceborne sounders. The basic physics of plasma-wave propagation and of active or passive antennas, in magnetoplasmas in laboratory or space, are important related topics. Investigations of geospace plasma density structures using injected whistler-mode and Z-mode waves are also solicited, as are reviews of earlier radio-sounding accomplishments highlighting outstanding questions yet to be addressed by radio sounders. There is a close connection between active experiments and space-borne sounding: near-field interactions with antennas in a plasma are very similar to high-power radio wave heating and stimulate a variety of resonances which need to be understood to optimize system function and which can also be used for diagnostic purposes. Contributions on such overlapping research areas are especially welcome.

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Commissions HGE - "Atmospheric, Ionospheric, Magnetospheric and High Energy Effects of Lightning Discharges"

Conveners: S. Celestin, N. Liu, M. Fullekrug

The recent discovery that lightning discharges can cause energetic radiation, relativistic particles, and transient luminous events has marked a profound advance in our understanding of the Earth's atmospheric electrodynamic behaviour. This session explores these novel processes and their impact on the atmosphere and the near-Earth environment. The session solicits contributions which advance knowledge in the areas of the global atmospheric electric circuit, lightning physics, transient luminous events, energetic radiation, relativistic particles, and their impact on the Earth's atmosphere, ionosphere and magnetosphere. One key focus of the session will be novel observations on board space platforms, such as the lightning imagers on geostationary satellites, the TARANIS satellite, the ASIM payload on the International Space Station, and related ground based observations and their modelling. Interdisciplinary studies which emphasize the connection between atmospheric layers and the relation between atmospheric electricity and climate change are particularly welcome.

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Commissions HJ - "Solar, Planetary, and Heliospheric Radio Emissions"

Conveners: P. Galopeau, G. Mann, H. O. Rucker, Y. Yan, S. White, T. Bastian

The Sun, solar system magnetized planets, and the heliosphere are sources of intense non-thermal radio emissions. Thus solar system radio astronomy and plasma physics provide most important tools that complement those of other space- or ground-based observations in Gamma rays, X-rays, EUV/UV, and the visible, etc., for understanding these non-thermal processes and energetic particles occurring in solar bursts and their influence from the solar surface to heliospheric space. New generation or upgraded radio telescopes, either solar-dedicated or non-solar-dedicated, have (will) come into use, including ALMA, E-OVSA, EVLA, GMRT, LOFAR, MUSER, and MWA, as well as the Ukrainian radio telescopes UTR-2, URAN, and GURT, the radio spectrometers aboard Stereo spacecraft, and the future SKA. These instruments provide new possibilities to measure the non-thermal radiation in an unprecedented way and open new windows for a better understanding of the radio emission processes in space (with applications to astrophysical objects, like supernovae remnants or active galactic nuclei). They also provide diagnostic tools for extrasolar planets, since these processes are the same basic plasma processes in space. Complementary studies are highly welcome including analysis from spaceborne experiments (e.g. Cassini, Galileo, Ulysses, Wind, Juno), laboratory and experimental studies, theoretical investigations devoted to the generation mechanisms and particle acceleration processes, and preparatory studies of forthcoming space missions (such as Bepi-Colombo and JUICE). Resonance, Solar Orbiter, Solar Probe, Taranis). This session will provide an important platform for solar radio astronomers, plasma physicists, planetary scientists, astrophysicists, and radio scientists to communicate and discuss a wide range of interesting and exciting topics, including the recent progress of radio observations of the Sun, solar wind, and planets, spacecraft measurements, data processing, theories, new technologies, and beyond.

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Commissions EFGH - "Natural Electromagnetic Noise and Radio Sensing Applications in Terrestrial and Planetary Environments"

Conveners: Y. Hobara, C. Price, T. Ushio, M. Fullerkrug

This joint session aims at presenting recent works on electromagnetic noise and phenomena in the terrestrial atmosphere and upper atmosphere (ionosphere/magnetosphere). Different kinds of electromagnetic noises will be dealt with, including atmospheric noises originated in lightning discharges (ELF Schumann resonances, mesospheric optical emissions etc.), man-made noise and noise due to wave-particle and wave-wave interactions. Corresponding electromagnetic noise environments on other planets are welcome. We are particularly interested in applications of natural EM observations in remote sensing such as monitoring, detecting and forecasting natural hazards, such as thunderstorms, severe weather, space weather and seismic events.

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Commissions EFGHJ - "One-Day Workshop on RFI Mitigation and Characterization"

Conveners: F. Gronwald, R. Bradley, T. Bullet, H. Rothkaehl, D. Le Vine, A. Maitra, M. Haredim, J. Gavan, V. Deniau, P. de Matthaeis

It is the aim of this workshop to bring together researchers, engineers and users from all radio science disciplines to consider how RFI affects their respective fields, to develop mitigation strategies, and to foster cooperation and collaboration. Particular attention will be given to the impact of new and future sources of RFI, spectrum management challenges, and new technology developments. Recent progress towards the ultimate goal of being able to do observations with real-time mitigation of the undesired signals, while leaving the desired signals minimally affected, will be discussed.

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Commissions GEH - "Seismo Electromagnetics (Lithosphere-Atmosphere- Ionosphere Coupling)"

Conveners: Sergey Pulinets, Yasuhide Hobara, Hanna Rothkaehl

The results of electromagnetic and ionospheric monitoring do not leave the place to doubts on the electromagnetic and ionospheric anomalies existence and their connection with seismic activity. Quasistationary electric fields, electromagnetic emissions in wide band of electromagnetic spectrum, anomalies of radio wave propagation, ionospheric anomalies are now the hot spots at all conferences of geophysical thematic. But still we lack the physical substantiation of many of registered effects. Multi‐parameter measurements in seismically active regions and cross validation of results obtained by different groups will help to understand the background physics of the observed anomalies. This session will accept papers demonstrating progress in understanding the ionospheric and electromagnetic effects preceding strong earthquakes including experimental findings and theoretical papers on lithosphere-atmosphere-ionosphere coupling.

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Commissions GH - "Meteors, Collisional EMPs, and Other Highly-Transient Space Plasma Events"

Conveners: John Mathews, Asta Pellinen-Wannberg

This session includes meteoroid impact EMP generation on satellite and planetary surfaces as well as the role of micrometeoroid processes (e.g., sputtering, fragmentation, ablation) and the mass flux on the upper atmosphere and ionosphere, as well as other related highly-transient phenomena. The radio and radar signatures of these processes are also considered.

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Commissions GH - "Plasma Instabilities in the Ionosphere"

Conveners: Frank Lind, Rob Pfaff

Plasma instabilities in the high, middle, and low latitude ionosphere play a key role in the development and evolution of structures in the Geospace environment, including processes in both the E and F regions. They often are associated with irregularities which can be experimentally observed using radar and radio techniques, as well as in-situ observations. Linear and non-linear theory is often used to predict instability thresholds, amplitudes, and velocities. Simulations have recently been quite successful in the detailed study of irregularity micro-structure, time evolution, and k-space behavior. This session will encourage discussion of new developments in the theoretical, simulation, and experimental observations relevant to the study and understanding of ionospheric plasma instabilities. The effects of ionospheric instabilities on other Geospace phenomena will also be of interest. This includes coupling to the magnetosphere and impacts of the lower atmosphere.

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Commissions GHJ - "Workshop on Extreme Space Weather Environments"

Workshop Chair: Mike Hapgood,
Workshop Co-Chair: Terry Onsager,
Conveners: Tony Mannucci, Viviane Pierrard, Mauro Messerotti, Ludwig Klein

Over recent years extreme space weather has been recognized as a global risk with significant societal and economic risks affecting many domains, including but not limited to electrical power grids, satellites, aircraft passengers and crew, avionics, GPS, Galileo and other GNSS positioning, navigation and timing systems and communications systems. In order to evaluate the consequences of space weather on these systems it is essential (a) to identify what are the factors in space weather environments that interact with the systems at risk, and then (b) to estimate what are reasonable worst cases for these factors. This workshop will bring together experts and other interested parties to review and refine a process for developing an internationally agreed set of specifications for the extreme space weather environment, and to test the process by applying it to a number of key domains. It is hoped that this will be the first of a series of workshops, hosted by different organizations and fora, developing these specifications.

The workshop will be led by Professor Mike Hapgood of the Rutherford Appleton Laboratory and will be hosted by URSI Commissions G, H and J. The focus will be on environments appropriate to the work of these Commissions, namely neutron, proton and electron fluxes, solar radio fluxes, ionospheric electron density enhancements, TEC and related electron gradients and radio scintillation. Talks and related presentations will be by invitation only, however, there will be plenty of opportunities for discussion and possibly for showing targeted data and information. Poster papers will be accepted.

The workshop will require additional registration on the URSI web site (but there is no additional cost). Additional preparatory materials will be sent out prior to the meeting.

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Commissions JEFGH - "Characterization and Mitigation of Radio Frequency Interference"

Conveners: Frank Gronwald, V. Deniau, Richard Bradley, Terry Bullet, Hanna Rothkaehl, David LeVine, Amit Kumar Mishra, M. Haredim, J. Gavan

In this session, radio frequency interference (RFI) issues will be discussed that are of particular importance for observational sciences such as radio astronomy, microwave remote sensing of the Earth, and solar and ionospheric studies where highly sensitive measurements are necessary.