A5014483219- Ionosphere and magnetosphere dynamics
- Solar and Space Plasma Dynamics
- Geomagnetism and Paleomagnetism Studies
- Earthquake Detection and Analysis
- Atmospheric Ozone and Climate
- Lightning and Electromagnetic Phenomena
- Geophysics and Gravity Measurements
- Astro and Planetary Science
- GNSS positioning and interference
- Planetary Science and Exploration
- Calibration and Measurement Techniques
- Photocathodes and Microchannel Plates
- Spacecraft Design and Technology
- Atmospheric aerosols and clouds
- Fire effects on ecosystems
- Impact of Light on Environment and Health
- Laser-induced spectroscopy and plasma
- Atmospheric chemistry and aerosols
- Atomic and Subatomic Physics Research
- Atmospheric and Environmental Gas Dynamics
- CCD and CMOS Imaging Sensors
- Seismic Waves and Analysis
- Gas Dynamics and Kinetic Theory
- Geophysics and Sensor Technology
- Meteorological Phenomena and Simulations
University of California, Berkeley
2016-2025
University of California System
2007-2016
Space Science Institute
2003-2011
National Central University
2009
Tohoku University
2001-2009
National Cheng Kung University
2009
Goddard Space Flight Center
2008
Technische Universität Braunschweig
2008
University of Calgary
2008
University of California, Los Angeles
2008
A newly discovered 1000‐km scale longitudinal variation in ionospheric densities is an unexpected and heretofore unexplained phenomenon. Here we show that vary with the strength of non‐migrating, diurnal atmospheric tides are, turn, driven mainly by weather tropics. strong connection between tropospheric conditions unexpected, as these upward propagating are damped far below peak density. The observations can be explained consideration dynamo interaction lower ionosphere (E‐layer) daytime....
Magnetospheric substorms explosively release solar wind energy previously stored in Earth's magnetotail, encompassing the entire magnetosphere and producing spectacular auroral displays. It has been unclear whether a substorm is triggered by disruption of electrical current flowing across near-Earth at â¼10 R E ( : Earth radius, or 6374 kilometers), process magnetic reconnection typically seen farther out â¼20 to 30 . We report on simultaneous measurements magnetotail multiple distances,...
Pulsating aurora, a spectacular emission that appears as blinking of the upper atmosphere in polar regions, is known to be excited by modulated, downward-streaming electrons. Despite its distinctive feature, identifying driver electron precipitation has been long-standing problem. Using coordinated satellite and ground-based all-sky imager observations from THEMIS mission, we provide direct evidence naturally occurring electromagnetic wave, lower-band chorus, can drive pulsating aurora....
A critical, long‐standing problem in substorm research is identification of the sequence events leading to auroral onset. Based on event and statistical analysis THEMIS all‐sky imager data, we show that there a distinct repeatable onset, having similarities important differences from previous ideas. The initiated by poleward boundary intensification (PBI) followed north‐south (N‐S) arc moving equatorward toward onset latitude. Because linkage fast magnetotail flows PBIs N‐S auroras, results...
Abstract The eruption of the Hunga Tonga‐Hunga Ha'apai volcano on 15 January 2022 triggered atmospheric waves at all altitudes. National Aeronautics and Space Administration Ionospheric Connection Explorer (ICON) European Agency Swarm satellites were well placed to observe its impact ionospheric wind dynamo. After Lamb wave entered dayside, A observed an eastward then westward equatorial electrojet (EEJ) two consecutive orbits, each with magnitudes exceeding 99.9th percentile typically...
The Far Ultraviolet Imager (FUV) on board the IMAGE satellite provides an instantaneous global view of OI 135.6‐nm nightglow with 2 min time resolution. Because emission from nighttime ionosphere is determined by line‐of‐sight integrated plasma density, images are useful for studying low‐latitude globally. With IMAGE/FUV observations March to June 2002, we have examined characteristics equatorial anomaly (EA) constructing a constant local map (LT map), in which pixels within assigned range...
Polarization electric fields created by the E‐ and F‐region dynamos cause uplift of plasma. The subsequent redistribution that plasma along magnetic field lines creates equatorial ionospheric anomaly (EIA). Observations post‐sunset EIA made IMAGE TIMED satellites are compared here with CHAMP, Ørsted SAC‐C observations noontime electrojet (EEJ). During magnetically quiet periods around equinox, EEJ show a remarkably similar four‐peaked wave‐like longitudinal variation. Its structure is...
We report the global transient luminous event (TLE) distributions and rates based on Imager of Sprites Upper Atmospheric Lightning (ISUAL) experiment onboard FORMOSAT‐2 satellite. ISUAL observations cover 45°S to 25°N latitude during northern summer 25°S 45°N winter. From July 2004 June 2007, recorded 5,434 elves, 633 sprites, 657 halos, 13 gigantic jets. Surprisingly, elve is dominant type TLEs, while sprites/halos are a distant second. Elve occurrence rate jumps as sea surface temperature...
A new instrument for all‐sky spectrophotometric imaging of aurora and airglow has been installed in the Air Force Geophysics Laboratory's Airborne ionospheric Observatory. Initial observations equatorial near‐equatorial 6300‐Å O I show existence north‐south aligned regions depletion. These dark bands often extend more than 1200 km direction 50–200 east‐west direction. They are observed to drift toward east during evening‐midnight hours, with one observation westward after local midnight....
A multipoint analysis of conjugate magnetospheric and ionospheric flow vortices during the formation substorm current wedge (SCW) on 19 February 2008 is presented. During substorm, four Time History Events Macroscale Interactions Substorms (THEMIS) spacecraft were located close to neutral sheet in premidnight region between 9 12 R E geocentric distance, which three closely (∼1–2 ) clustered at ∼23 MLT one was farther west ∼21 MLT. The engulfed by a counterclockwise plasma vortex, while...
There are at least four distinct regions of auroral particle precipitation. The oval and nightside proton aurora well known; they separated in the evening sector overlap morning sector. is a zone soft-electron precipitation latitudes above where ∼0.5-kev electrons precipitate; no protons observed this region. Electron energies soft decrease systematically with latitude (for given Kp). (∼100–200 ev) soft-proton near midday meridian, these particles probably come directly from magnetosheath....
[1] Thermospheric O/N2 column density ratios referenced at a N2 of 1017 cm−2 are obtained using the IMAGE SI-13 and TIMED/GUVI far-ultraviolet (FUV) dayglow data, AURIC simulation results, MSIS86 model. Each magnetic storms occurring during 4-day period (1–4 October 2002) caused significant depletion that was detected by both GUVI instruments. The extended down to latitudes 10° −5° in Northern Southern Hemispheres, respectively. Simultaneous measurements show an excellent agreement between...
The IMAGE spacecraft uses photon and neutral atom imaging radio sounding techniques to provide global images of Earth's inner magnetosphere upper atmosphere. Auroral at ultraviolet wavelengths shows that the proton aurora is displaced equatorward with respect electron discrete auroral forms higher latitudes are caused almost completely by electrons. Energetic ions injected into during magnetospheric disturbances a strong energy-dependent drift leads formation ring current in several tens...
On March 18, 2002, under northward interplanetary magnetic field (IMF) and high (∼15 nPa) solar wind dynamic pressure conditions, Cluster observed reconnection signatures the passage of an X‐line at large (∼175°) magnetic‐shear high‐latitude magnetopause (MP). The observations are consistent with occurrence a site tailward cusp in vicinity spacecraft. At same time IMAGE bright spot poleward dayside auroral oval resulting from precipitating protons into atmosphere. intensity proton is energy...