A5070333810- Ionosphere and magnetosphere dynamics
- Solar and Space Plasma Dynamics
- Geomagnetism and Paleomagnetism Studies
- Earthquake Detection and Analysis
- Geophysics and Gravity Measurements
- Atmospheric Ozone and Climate
- Ocean Waves and Remote Sensing
- Astro and Planetary Science
- GNSS positioning and interference
- Magnetic confinement fusion research
- Seismic Waves and Analysis
- Methane Hydrates and Related Phenomena
- Lightning and Electromagnetic Phenomena
- Atmospheric chemistry and aerosols
- Atmospheric and Environmental Gas Dynamics
- Particle accelerators and beam dynamics
- Astrophysics and Cosmic Phenomena
- Magnetic Field Sensors Techniques
- Atomic and Subatomic Physics Research
- Oceanographic and Atmospheric Processes
- Geophysics and Sensor Technology
- Electromagnetic Compatibility and Measurements
- Pulsars and Gravitational Waves Research
- Inertial Sensor and Navigation
- Geophysical and Geoelectrical Methods
Augsburg University
2016-2025
University of Augsburg
2020-2025
University of Michigan
2018-2023
Space Science Institute
2018-2023
Charles River Laboratories (Netherlands)
2015-2019
John Wiley & Sons (United States)
2018
University of Colorado Boulder
2018
Rutherford Appleton Laboratory
2018
University of Minnesota System
2002
Yu.G. Shafer Institute of Cosmophysical Research and Aeronomy
1999
Three‐component dynamic spectrograms (0–80 mHz) of AMPTE/CCE magnetic field data from August 24, 1984, through December 7, 1985, have been used to survey ULF pulsation activity occurring L = 5 9 in the equatorial magnetosphere (±16° latitude) at all local times. The were scanned visually, and each half‐hour interval was categorized by spectral type, approximate polarization, intensity, spacecraft location produce a base representing 7231 hours observations. Coherent pulsations are divided...
The dipole configuration of the Earth's magnetic field allows for trapping highly energetic particles, which form radiation belts. Although significant advances have been made in understanding acceleration mechanisms belts, loss processes remain poorly understood. Unique observations on 17 January 2013 provide detailed information throughout belts energy spectrum and pitch angle (angle between velocity a particle field) distribution electrons up to ultra-relativistic energies. Here we show...
The Cluster spacecraft were favorably positioned on the nightside near equatorial plasmapause of Earth at L ∼ 4.3 30 March 2002 to observe electromagnetic ion cyclotron (EMIC) rising tone emissions in association with Pc1 waves 1.5 Hz. EMIC found be left‐hand, circularly polarized, dispersive, and propagating away from equator. Their burstiness dispersion ∼30s/Hz out Hz are consistent their identification as triggered chorus emissions, first reported through situ observations plasmapause....
Abstract Although most studies of the effects electromagnetic ion cyclotron (EMIC) waves on Earth's outer radiation belt have focused events in afternoon sector plasmasphere or plume region, strong magnetospheric compressions provide an additional stimulus for EMIC wave generation across a large range local times and L shells. We present here observations event 23 February 2014 that extended over 8 h UT 12 time, stimulated by gradual 4 rise subsequent sharp increases solar wind pressure....
[1] With data from the Canadian Magnetic Observatory System, Array for Real time Investigations of Activity, Geophysical Institute Magnetometer Array, Greenland, Time History Events and Macroscale Interactions during Substorms (THEMIS), Cusp Cleft Studies ground magnetometer arrays, we applied state-of-art technique on basis spherical elementary currents systems (SECS) developed by Amm Viljanen (1999) in order to calculate maps ionospheric equivalent over whole North American auroral region....
Abstract Electromagnetic ion cyclotron (EMIC) waves have been suggested to be a cause of radiation belt electron loss the atmosphere. Here simultaneous, magnetically conjugate measurements are presented EMIC wave activity, measured at geosynchronous orbit and on ground, energetic precipitation, seen by Balloon Array for Radiation Relativistic Electron Losses (BARREL) campaign, two consecutive days in January 2013. Multiple bursts precipitation were observed duskside magnetosphere end 18...
Abstract We simulate the radiation belt electron flux enhancements during selected Geospace Environment Modeling (GEM) challenge events to quantitatively compare major processes involved in relativistic acceleration under different conditions. Van Allen Probes observed significant enhancement both storm time of 17–18 March 2013 and non–storm 19–20 September 2013, but distributions plasma waves energetic electrons for two were dramatically different. During SYM ‐ H minimum reached −130 nT,...
The plasmas (electrons and ions) in the inner magnetosphere have wide energy ranges from electron volts to mega-electron (MeV). These rotate around Earth longitudinally due gradient curvature of geomagnetic field by co-rotation motion with timescales several tens hours less than 10 min. They interact plasma waves at frequencies mHz kHz mainly equatorial plane magnetosphere, obtain energies up MeV, are lost into ionosphere. In order provide global distribution quantitative evaluation...
We have calculated the integrated ULF wave power in Pc5 band at two stations, Kevo (part of International Monitor for Auroral Geomagnetic Effects (IMAGE) magnetometer array Scandinavia, auroral zone latitudes), and Cape Dorset Magnetometer Array Cusp Cleft Studies (MACCS) Arctic Canada, cusp compared this against solar wind velocity last six months 1993, a period characterized by persistent high‐speed streams. find both local noon Dorset, morning Kevo, (0.002 – 0.010 Hz) over six‐hour...
Spectrograms of ULF waves in the 0 to 80 mHz frequency range have been prepared from magnetic field data obtained by elliptically orbiting AMPTE/CCE satellite (with an apogee approximately 8.8 R e . The most prominent feature these spectrograms (which cover a full 15.6 hour orbit) is presence harmonically structured, azimuthally polarized pulsations outer magnetosphere during daytime hours. frequencies decrease with increasing radial distance earth, indicating that they represent independent...
We develop a nonlinear wave growth theory of electromagnetic ion cyclotron (EMIC) triggered emissions observed in the inner magnetosphere. first derive basic equations from Maxwell's and momentum for electrons ions. then obtain that describe dynamics resonant protons interacting with an EMIC wave. The frequency sweep rate plays important role forming current controls growth. Assuming optimum condition maximum as absolute instability at magnetic equator self‐sustaining propagating equator, we...
Ion conic distributions are often observed in the cusp/cleft region of dayside magnetosphere. We show that these ions can be heated via process cyclotron resonance with broadband low‐frequency (near ion gyrofrequency) waves. Data from two crossings polar‐orbiting DE 1 satellite studied detail. There is very good agreement between onset waves and heating. Observed cool O + wave intensities one orbit used as input to a Monte Carlo simulation. Given assumptions underlying simulation model,...
Magnetic pulsations in the Pc1–Pc2 frequency range (0.1–5 Hz) are often observed on ground and Earth's magnetosphere during aftermath of geomagnetic storms. Numerous studies have suggested that they may play a role reducing fluxes energetic ions ring current; more recent suggest interact parasitically with radiation belt electrons as well. We report here observations 2005 from search coil magnetometers riometers installed at three Antarctic stations, Halley (−61.84° magnetic latitude, MLAT),...
Abstract Electromagnetic ion cyclotron (EMIC) waves were observed at multiple observatory locations for several hours on 17 January 2013. During the wave activity period, a duskside relativistic electron precipitation (REP) event was by one of Balloon Array Radiation belt Relativistic Electron Losses (BARREL) balloons and magnetically mapped close to Geostationary Operational Environmental Satellite (GOES) 13. We simulate pitch angle diffusion caused gyroresonant interactions with EMIC using...
Geomagnetically induced currents (GICs) represent a significant challenge for society on stable electricity supply. Space weather activates global electromagnetic and plasma processes in the near-Earth environment, however, highest risk of GICs is related not directly to those with enormous energy yield, but too much weaker, fast, processes. Here we consider several typical examples such fast their impact power transmission lines Kola Peninsula Karelia: interplanetary shocks; traveling...
Abstract Electromagnetic ion cyclotron (EMIC) waves can drive precipitation of tens keV protons and relativistic electrons, are a potential candidate for causing radiation belt flux dropouts. In this study, we quantitatively analyze three cases EMIC‐driven precipitation, which occurred near the dusk sector observed by multiple Low‐Earth‐Orbiting (LEO) Polar Operational Environmental Satellites/Meteorological satellite programme (POES/MetOp) satellites. During EMIC wave activity, proton from...
Abstract On 31 May 2013 several rising tone electromagnetic ion cyclotron (EMIC) waves with intervals of pulsations diminishing periods were observed in the magnetic local time afternoon and evening sectors during onset a moderate/large geomagnetic storm. The sequentially Finland, Antarctica, western Canada. Coincident electron precipitation by network ground‐based Antarctic Arctic Radiation‐belt Dynamic Deposition VLF Atmospheric Research Konsortia riometer instruments, as well...
Abstract We present a statistical survey of the latitudinal structure fast magnetosonic wave mode detected by Van Allen Probes spanning time interval 21 September 2012 to 1 August 2014. show that statistically, occurrence frequency ( f ) normalized local proton cyclotron cP has distinct funnel‐shaped appearance in latitude about magnetic equator similar found case studies. By comparing observed E/B ratios with model ratio, using plasma density and background field magnitude as input we this...
We have used magnetometer data from 10 locations in Arctic Canada and Greenland, covering over 5 hours magnetic local time at latitudes 75° to 79°, characterize the dayside patterns of enhanced long‐period ULF (10‐ 600‐s period) wave power cusp/cleft latitudes. conclude following: (1) In agreement with earlier single‐station studies, we find that most common type is broadband noise (Pi 1‐2). Distinct Pc 3‐4 activity more sustained monochromatic are apparent when this weak. (2) Multistation...
Analysis of high time resolution magnetometer data from the Polar satellite and an array high‐latitude ground stations in Antarctica has identified 20 simultaneously observed Pc 1–2 wave events outer dayside magnetosphere during first 17 months operations. In contrast to most earlier studies waves, based on equatorial satellites near apogee which moved only slowly across L shells if at all, initial orbit allowed it rapidly cross magnetospheric shells, but significantly away magnetic equator....
This paper describes the development of a major space storm during November 2–11, 1993. We discuss history contributing high‐speed stream, powerful combination solar wind transients and corotating interaction region which initiated storm, flow prolonged near‐Earth manifestations storm. The 8‐day period was unusually long; result stream (maximum speed 800 km/s) emanating from distended coronal hole. Storm onset accompanied by compression entire dayside magnetopause to within geosynchronous...
“Upstream waves,” generated in the solar wind upstream of a quasi‐parallel bow shook, are believed to be major source Pc 3‐4 pulsation activity observed dayside magnetosphere. In an attempt better understand means by which “upstream wave” energy is transmitted from into magnetosphere, we compared simultaneous data ISEE 1 and 2 wind, AMPTE IRM subsolar magnetosheath, CCE Our observations indicate that magnetospheric low IMF cone angles associated with increased turbulence magnetosheath...