A5027172954- Ionosphere and magnetosphere dynamics
- Solar and Space Plasma Dynamics
- Geomagnetism and Paleomagnetism Studies
- Earthquake Detection and Analysis
- Astro and Planetary Science
- Magnetic confinement fusion research
- Dust and Plasma Wave Phenomena
- Lightning and Electromagnetic Phenomena
- Laser-induced spectroscopy and plasma
- Geophysics and Gravity Measurements
- Plasma Diagnostics and Applications
- Magnetic Field Sensors Techniques
- Seismic Waves and Analysis
- Atomic and Molecular Physics
- Geophysics and Sensor Technology
- earthquake and tectonic studies
- GNSS positioning and interference
- Laser-Plasma Interactions and Diagnostics
- Solar Radiation and Photovoltaics
- Planetary Science and Exploration
- Gamma-ray bursts and supernovae
- Geophysical and Geoelectrical Methods
- Astrophysics and Cosmic Phenomena
- Atmospheric Ozone and Climate
- Spacecraft Design and Technology
University of California, Berkeley
2015-2024
Space Research Institute
2016-2022
Planetary Science Institute
2022
National Research University Higher School of Economics
2022
Lomonosov Moscow State University
2021
Berkeley College
2019-2020
University of California, Los Angeles
2020
Russian Academy of Sciences
2020
New Jersey Institute of Technology
2020
Space Science Institute
2001-2016
Small-amplitude double layers and solitary waves containing magnetic-field-aligned electric field components have been observed for the first time in auroral plasma between altitudes of 6000 8000 km association with electron ion velocity distributions that indicate presence fields parallel to magnetic field. The may account a large portion potential drop accelerates particles.
dc and ac plasma-density vector-electric-field detectors on a polar orbiting satellite have measured spatially confined regions of extremely large (\ensuremath{\sim}\textonehalf{} V/m) electric fields in the auroral zone at altitudes below 8000 km. Such frequently double structures opposing containing characteristic different wave spectra internal external to themselves. These are identified as paired electrostatic shocks which associated with ion cyclotron turbulence.
We report observations of “fast solitary waves” that are ubiquitous in downward current regions the mid‐altitude auroral zone. The single‐period structures have large amplitudes (up to 2.5 V/m), travel much faster than ion acoustic speed, carry substantial potentials ∼100 Volts), and associated with strong modulations energetic electron fluxes. amplitude speed distinguishes them from ion‐acoustic waves or weak double layers. electromagnetic signature appears be an positive charge (electron...
Magnetohydrodynamic (MHD) turbulence in the solar wind is observed to show spectral behavior of classical Kolmogorov fluid over an inertial subrange and departures from this at short wavelengths, where energy should be dissipated. Here we present first measurements electric field fluctuation spectrum dissipative wave number ranges a Beta > or approximately = 1 plasma. The k(-5/3) agrees strikingly with magnetic spectrum; phase speed regime shown consistent Alfvén speed. At smaller...
The Electric Fields and Waves (EFW) Instruments on the two Radiation Belt Storm Probe (RBSP) spacecraft (recently renamed Van Allen Probes) are designed to measure three dimensional quasi-static low frequency electric fields waves associated with major mechanisms responsible for acceleration of energetic charged particles in inner magnetosphere Earth. For this measurement, instrument uses pairs spherical double probe sensors at ends orthogonal centripetally deployed booms spin plane...
The nature of small-scale turbulent fluctuations in the solar wind is investigated using a comparison Cluster magnetic and electric field measurements to predictions arising from models consisting either kinetic Alfvén waves or whistler waves. properties these linear theory are used construct spacecraft-frame frequency spectra (|δE|/|δB|)s/c (|δB∥|/|δB|)s/c, allowing for direct spacecraft data. measured fluctuations, found be inconsistent with wave model, agree well prediction spectrum...
On 1 April 2001, the Polar satellite crossed a subsolar magnetopause associated with antiparallel magnetic fields. Over width approximately 6 magnetosheath ion skin depths (approximately 3 magnetospheric depths), perpendicular flows different from E x B/B(2) as well Hall and electric field signatures were observed. At smaller scale, electron flow decoupled near deep minimum in strength. Separatrices identified boundaries of low frequency turbulence density minima parallel The reconnection...
Abstract. Highlights are presented from studies of the electric field data various regions along Cluster orbit. They all point towards a very high coherence for phenomena recorded on four spacecraft that separated by few hundred kilometers structures over whole range apparent frequencies 1 mHz to 9 kHz. This presents completely new opportunities study spatial-temporal plasma magnetosphere out solar wind. A probe environment was constructed CLUSTER experiment now produces unprecedented...
We present evidence based on measurements from the Polar spacecraft for existence of small‐scale, large‐amplitude kinetic Alfvén waves/spikes at plasma sheet boundary layer (PSBL) altitudes 4–6 R E . These structures coincide with larger‐scale Alfvénic waves that carry a large net Poynting flux along magnetic field lines toward Earth. Both are typically observed in PSBL but have also been deeper sheet. The small‐scale spikes electric amplitudes up to 300 mV m −1 and associated variations...
Observations of plasma particles and fields by the FAST satellite find evidence acceleration intense upgoing electron beams quasi‐static parallel electric fields. The beam characteristics include a broad energy spectrum with peak energies between 100 eV 5 keV, perpendicular temperatures less than 1 eV, fluxes greater 10 9 /cm²sec. Diverging electrostatic shocks associated have integrated potentials that match energy. These are found in regions downward Birkeland current account for total...
In this paper, we present measurements from two passes of the Polar spacecraft intense electric and magnetic field structures associated with Alfven waves at within outer boundary plasma sheet geocentric distances 4–6 R E near local midnight. The variations have maximum values exceeding 100 mV/m are typically polarized approximately normal to boundary. investigated vary over timescales (in frame) ranging 1 30 s. They strong fluctuations amplitudes 10–40 nT which lie predominantly in plane...
Measurements from the Cluster spacecraft of electric fields, magnetic and ions are used to study structure dynamics reconnection region in tail at distances ∼18 R E near 22.4 MLT on 1 October 2001. This paper focuses measurements large amplitude normal component field observed ion decoupling x‐line, associated potential drops across current sheet, role electrostatic ballistic acceleration sheet. The thinnest sheet during this interval was bifurcated into a pair sheets measured width...
Electric field and energetic particle observations by the Fast Auroral Snapshot (FAST) satellite provide convincing evidence of acceleration quasi‐static, magnetic‐field‐aligned (parallel) electric fields in both upward downward current regions auroral zone. We demonstrate this comparing inferred parallel potentials electrostatic shocks with energies. also report nonlinear structures which may play a role supporting fields. These include large‐amplitude ion cyclotron waves region, intense,...
We report a new type of spatially coherent plasma structure that is associated with quasistatic, magnetic-field-aligned electric fields in space plasmas. The solitary structures form magnetized plasma, are multidimensional, and highly supersonic. size along ${\mathbf{B}}_{0}$ few ${\ensuremath{\lambda}}_{D}$ increases increasing amplitude, unlike classical soliton. perpendicular appears to be influenced by ion motion. show the facilitate ion-electron momentum exchange suggest an aggregate...
The Polar Satellite carries the first three-axis electric field detector flown in magnetosphere. Its direct measurement of components perpendicular and parallel to local magnetic has revealed new classes features structures associated with plasma acceleration that produces discrete auroras populates magnetosphere ionospheric origin. These structures, hydrogen ion cyclotron mode, include very large solitary waves, spiky wave envelopes fields, amplitude, nonlinear, coherent waves.
The wave plasma experiment onboard satellite S3‐3 has detected electrostatic hydrogen cyclotron waves at altitudes near 1R E in the Earth’s polar magnetosphere. observed properties are excellent agreement with theoretical dispersion relation as well linear instability theory for current driven ion and used to determine that is more than 90% hydrogen, electron temperature about 3.5 volts T e /T 1 range of or larger. strongest events associated large ⩾120mV/m) Dc electric fields described an...
Characteristics of solitary waves observed by Polar in the high altitude cusp, polar cap and plasma sheet boundary are reported compared to observations auroral zone. The study presented herein shows that, at altitudes, positive potential structures (electron holes), with scale sizes order 10's Debye lengths, which usually propagate velocities a few thousand km/s. At boundary, direction propagation can be either upward or downward; whereas leading edge cusp energetic particle injections, it...