A5066804484- Astro and Planetary Science
- Solar and Space Plasma Dynamics
- Planetary Science and Exploration
- Ionosphere and magnetosphere dynamics
- Geomagnetism and Paleomagnetism Studies
- Space Science and Extraterrestrial Life
- Geophysics and Gravity Measurements
- Space Exploration and Technology
- Stellar, planetary, and galactic studies
- Space exploration and regulation
- Earthquake Detection and Analysis
- Solar Radiation and Photovoltaics
- Laser-induced spectroscopy and plasma
- Spacecraft Design and Technology
- Atmospheric Ozone and Climate
- Space Satellite Systems and Control
- Isotope Analysis in Ecology
- Spaceflight effects on biology
- Scientific Research and Discoveries
- Gamma-ray bursts and supernovae
- Global Energy and Sustainability Research
- Astrophysics and Cosmic Phenomena
- Spacecraft and Cryogenic Technologies
- Atomic and Molecular Physics
- Photovoltaic System Optimization Techniques
University of California, Berkeley
2016-2025
Berkeley College
2008-2023
Jet Propulsion Laboratory
2021
Super Stars Literacy
2021
Ames Research Center
2021
Planetary Science Institute
1991-2016
University of California System
2004-2015
Space Science Institute
2003-2015
University of California, Los Angeles
1989-2011
Institute of Geophysics
1987-2011
The Cassini spacecraft passed within 168.2 kilometers of the surface above southern hemisphere at 19:55:22 universal time coordinated on 14 July 2005 during its closest approach to Enceladus. Before and after this time, a substantial atmospheric plume coma were observed, detectable in Ion Neutral Mass Spectrometer (INMS) data set out distance over 4000 from INMS indicate that are dominated by water, with significant amounts carbon dioxide, an unidentified species mass-to-charge ratio 28...
The Cassini Ion Neutral Mass Spectrometer (INMS) has obtained the first in situ composition measurements of neutral densities molecular nitrogen, methane, hydrogen, argon, and a host stable carbon-nitrile compounds Titan's upper atmosphere. INMS mass spectrometry also provided evidence for atmospheric waves atmosphere direct isotopes carbon, which reveal interesting clues about evolution bulk thermal structure moon's do not appear to have changed considerably since Voyager 1 flyby.
Measurements from electrostatic analyzers aboard the polar‐orbiting S3‐3 satellite have been tabulated to form a synoptic picture of occurrence upgoing 90eV 3.9keV auroral ions. In this survey, distinction is made between ion distributions having peak fluxes along B (beams) and those exhibiting flux maxima that are not field‐aligned (conics). It shown both beams conics common phenomena, whose frequencies in latitude, local time, altitude marked dependence on magnetic activity. During quiet...
Abstract We report on the in‐flight performance of Solar Wind Ion Analyzer (SWIA) and observations Mars‐solar wind interaction made during Mars Atmosphere Volatile EvolutioN (MAVEN) prime mission a portion its extended mission, covering 0.85 Martian years. describe data products returned by SWIA discuss proper handling measurements with different mechanical attenuator states telemetry modes, effects penetrating scattered backgrounds, limited phase space coverage, multi‐ion populations...
Coupling between the lower and upper atmosphere, combined with loss of gas from atmosphere to space, likely contributed thin, cold, dry modern Mars. To help understand ongoing ion Mars Atmosphere Volatile Evolution (MAVEN) spacecraft made comprehensive measurements ionosphere, interactions Sun solar wind during an interplanetary coronal mass ejection impact in March 2015. Responses include changes bow shock magnetosheath, formation widespread diffuse aurora, enhancement pick-up ions....
The Interstellar Mapping and Acceleration Probe (IMAP) is a revolutionary mission that simultaneously investigates two of the most important overarching issues in Heliophysics today: acceleration energetic particles interaction solar wind with local interstellar medium. While seemingly disparate, these are intimately coupled because accelerated inner heliosphere play critical roles outer heliospheric interaction. Selected by NASA 2018, IMAP planned to launch 2024. spacecraft simple...
Abstract We present observations by the Mars Atmosphere and Volatile EvolutioN (MAVEN) mission of a substantial plume‐like distribution escaping ions from Martian atmosphere, organized upstream solar wind convection electric field. From case study MAVEN particle‐and‐field data during one spacecraft orbit, we identified three planetary ion populations: plume fluxes mainly along field over north pole region Mars‐Sun‐Electric (MSE) coordinate system, antisunward in tail region, much weaker...
The IMPACT (In situ Measurements of Particles And CME Transients) investigation on the STEREO mission was designed and developed to provide multipoint solar wind suprathermal electron, interplanetary magnetic field, energetic particle information required unravel nature coronal mass ejections their heliospheric consequences. consists seven individual sensors which are packaged into a boom suite, SEP suite. This review summarizes science objectives IMPACT, instruments that comprise...
Models of the magnetospheric and magnetosheath magnetic fields are used to determine relative orientations these at dayside magnetopause in order locate potential merging sites. Areas on with different fractional antiparallel components displayed by contour diagrams for a variety interplanetary field orientations. For oriented perpendicular solar wind velocity areas nearly agree those obtained Crooker using simplified representations geometry. Here, application more realistic models gives...
The large-scale, steady-state magnetic field configuration of the solar corona is typically computed using boundary conditions derived from photospheric observations. Two approaches are used: (1) potential source surface (PFSS) models, and (2) magnetohydrodynamic (MHD) models. former have advantage that they simple to develop implement, require relatively modest computer resources, can resolve structure on scales beyond those be handled by current MHD However, been criticized because their...
Nonthermal processes such as dissociative recombination of ionospheric molecules are known to lead loss atmospheric constituents (N, O, C) at Mars where the gravitational potential is easily overcome by energy imparted product atoms. Moreover, observations escaping planetary ions on PHOBOS‐2 spacecraft showed that solar wind presently scavenging significant amounts both oxygen and molecular species it flows past planet. Because sun atmosphere have changed over time, evolutionary importance...
We present the extension of magnetic breakout model for CME initiation to a fully three-dimensional, spherical geometry. Given increased complexity dynamic field interactions in three dimensions, we first summary well known axisymmetric scenario terms topological evolution associated with various phases eruptive process. In this context, discuss analogous during process simplest three-dimensional multipolar system. show that an extended bipolar active region embedded oppositely directed...
The Analyzer of Space Plasma and Energetic Atoms (ASPERA) on board the Mars Express spacecraft found that solar wind plasma accelerated ionospheric ions may be observed all way down to pericenter 270 kilometers above dayside planetary surface. This is very deep in ionosphere, implying direct exposure martian topside atmosphere forcing. low-altitude penetration energization due irregularities or perturbations, magnetic anomalies at Mars, both.
The fluxes and energy spectra of picked‐up planetary O+ ions incident on the dayside atmospheres Venus Mars are calculated using neutral exosphere models Nagy Cravens (1988) Spreiter Stahara (1980) gasdynamic model magnetosheath electric magnetic field. Cold (∼10 eV) O + launched from hemispherical grids starting points covering daysides planets their trajectories followed until they either impact “obstacle” or cross terminator plane. impacting, precipitating, ion weighted according to...
We present Cassini Ion and Neutral Mass Spectrometer (INMS) measurements of ion densities on the nightside Titan from April 16, 2005, show that a substantial ionosphere exists complex chemistry is operating there. The total ionospheric measured both by INMS Radio Plasma Wave (RPWS) experiments suggest precipitation magnetosphere into atmosphere electrons with energies ranging 25 eV up to about 2 keV taking place. absence composition has been major obstacle understanding ionosphere. Seven...