A5035475262- Planetary Science and Exploration
- Atmospheric Ozone and Climate
- Astro and Planetary Science
- Ionosphere and magnetosphere dynamics
- Solar and Space Plasma Dynamics
- Atmospheric and Environmental Gas Dynamics
- Space Exploration and Technology
- Geophysics and Gravity Measurements
- Earthquake Detection and Analysis
- Spaceflight effects on biology
- Space Science and Extraterrestrial Life
- Calibration and Measurement Techniques
- Atomic and Molecular Physics
- Nuclear physics research studies
- Scientific Research and Discoveries
- Solar Radiation and Photovoltaics
- Electron and X-Ray Spectroscopy Techniques
- Geomagnetism and Paleomagnetism Studies
- Atmospheric chemistry and aerosols
- Spacecraft and Cryogenic Technologies
- Spectroscopy and Laser Applications
- X-ray Spectroscopy and Fluorescence Analysis
- Meteorological Phenomena and Simulations
- Climate variability and models
- Ga2O3 and related materials
Computational Physics (United States)
2016-2025
Environment Agency Abu Dhabi
2023
The Center for Public Integrity
2017
University of Liège
2017
Langley Research Center
1963-1970
Princeton University
1965-1969
Princeton Plasma Physics Laboratory
1966-1969
The Earth's thermosphere and ionosphere constitute a dynamic system that varies daily in response to energy inputs from above below. This can exhibit significant within an hour changes those inputs, as plasma fluid processes compete control its temperature, composition, structure. Within this system, short wavelength solar radiation charged particles the magnetosphere deposit energy, waves propagating lower atmosphere dissipate. Understanding global-scale of thermosphere-ionosphere (T-I)...
Abstract After days of intense solar activity, active region AR3664 launched seven CMEs toward Earth producing an extreme G5 geomagnetic storm commencing at 17:05 UT on 10 May 2024. The impacted power grids, disrupted precision navigational systems used by farming equipment, and generated aurora seen around the globe. produced remarkable effects composition, temperature, dynamics in Earth's thermosphere that were observed NASA's Global‐scale Observations Limb Disk (GOLD) mission are reported...
Simultaneous measurements of disk‐viewing OI 135.6 nm and N 2 Lyman‐Birge‐Hopfield (LBH) dayglow can be used to monitor the solar EUV flux Q column abundance thermospheric O relative (O/N ). We report on a study that quantifies relationships between these emissions above parameters. Emission is considered from 134.5 139.0 (designated nm) 155.0 170.0 as LBH) at resolution 3.6 nm. The intervals were chosen for analysis satellite data reported in companion paper by Evans et al. (this issue)....
Planetary auroras reveal the complex interplay between an atmosphere and surrounding plasma environment. We report discovery of low-altitude, diffuse spanning much Mars' northern hemisphere, coincident with a solar energetic particle outburst. The Imaging Ultraviolet Spectrograph, remote sensing instrument on Mars Atmosphere Volatile Evolution (MAVEN) spacecraft, detected auroral emission in virtually all nightside observations for ~5 days, nearly geographic longitudes. Emission extended...
Abstract The NASA Global‐scale Observations of the Limb and Disk (GOLD) mission has flown an ultraviolet‐imaging spectrograph on SES‐14, a communications satellite in geostationary orbit at 47.5°W longitude. That instrument observes Earth's far ultraviolet (FUV) airglow ~134–162 nm using two identical channels. observations performed include limb scans, stellar occultations, images sunlit nightside disk from 6:10 to 00:40 universal time each day. Initial analyses reveal interesting...
Abstract We report a comprehensive study of Mars dayglow observations focusing on upper atmospheric structure and seasonal variability. analyzed 744 vertical brightness profiles comprised ∼109,300 spectra obtained with the Imaging Ultraviolet Spectrograph (IUVS) aboard Atmosphere Volatile EvolutioN (MAVEN) satellite. The emission show features similar to previous UV measurements at Mars. find significant drop in thermospheric scale height temperature between L S = 218° 337–352°, attributed...
Abstract Observations of far‐ultraviolet (FUV) dayglow by the Global‐scale Limb and Disk (GOLD) mission provide an opportunity for quantifying global‐scale response thermosphere to solar extreme‐ultraviolet variability geomagnetic activity. Relative temperature changes can be measured monitoring in rotational structure observed molecular nitrogen Lyman‐Birge‐Hopfield (LBH) band emissions. We present a new technique deriving effective neutral temperatures from GOLD FUV observations using...
[1] New models of solar extreme ultraviolet (EUV) irradiance variability are constructed in 1 nm bins from 0 to 120 using multiple regression the Mg II and F10.7 activity indices with observations made during descending phase cycle 23. The have been used reconstruct EUV spectra daily since 1950, annually 1610, forecast estimate future levels 24. A two-component model developed by scaling observed rotational modulation two underestimates changes that Solar Experiment (SEE) reports at...
Abstract The Global‐scale Observations of the Limb and Disk (GOLD) is a National Aeronautics Space Administration mission opportunity designed to study how Earth's ionosphere‐thermosphere system responds geomagnetic storms, solar radiation, upward propagating atmospheric tides waves. GOLD employs two identical ultraviolet spectrographs that make observations thermosphere ionosphere from commercial communications satellite owned operated by Société Européenne des Satellites (SES) located in...
Abstract Observations of far‐ultraviolet (FUV) dayglow by the Global‐scale Limb and Disk (GOLD) mission provide a new opportunity to monitor relative composition changes in upper atmosphere as well solar extreme ultraviolet (EUV) variability. Relative are quantified ΣO/N 2 , column density ratio atomic oxygen molecular nitrogen, while Q EUV provides measure energy flux from 1 45 nm into atmosphere. This spectral range ionizing radiation which ultimately results FUV airglow emission produced...
Abstract We report the detection of intense emission from magnesium and iron in Mars' atmosphere caused by a meteor shower following Comet Siding Spring's close encounter with Mars. The observations were made Imaging Ultraviolet Spectrograph, remote sensing instrument on Mars Atmosphere Volatile EvolutioN spacecraft orbiting Ionized brightest planet's for many hours, resulting resonant scattering solar ultraviolet light. Modeling suggests substantial fluence low‐density dust particles 1–100...
The decay of the ${2}^{\ensuremath{-}}$ and ${7}^{+}$ isomeric states ${\mathrm{Tl}}^{192}$, ${\mathrm{Tl}}^{194}$, ${\mathrm{Tl}}^{196}$, ${\mathrm{Tl}}^{198}$ has been studied, using isotopically separated sources produced by high-energy proton spallation lead uranium targets. $\ensuremath{\gamma}$-ray conversion-electron spectra have recorded, extensive coincidence measurements helped to establish energy levels that are populated in corresponding mercury daughter nuclides. Level schemes...
Abstract We report the detection of bright aurora spanning Mars' nightside during space weather event occurring in September 2017. The phenomenon was similar to diffuse detected previously at Mars, but 25 times brighter and detectable over entire visible nightside. observations were made with Imaging UltraViolet Spectrograph, a remote sensing instrument on Mars Atmosphere Volatile EvolutioN spacecraft orbiting Mars. Images show that emission brightest around limb planet, fairly uniform faint...
Abstract Using the Mars Atmospheric and Volatile EvolutioN mission (MAVEN) Imaging Ultraviolet Spectrograph (IUVS), we found periodic longitudinal variations in CO 2 density Martian atmosphere. These are derived from observations of ( ) emission limb scans 100–190 km altitude range. The exhibit significant structure with wave numbers 1, 2, 3 an effectively constant local solar time frame, attribute this to nonmigrating tides. wave‐2 component is dominated by diurnal eastward moving DE1 tide...
Abstract We present the first observations of dayside coronal oxygen emission in far ultraviolet (FUV) measured by Emirates Mars Ultraviolet Spectrometer (EMUS) onboard Mission (EMM). The high sensitivity EMUS is providing an opportunity to observe tenuous corona FUV, which otherwise difficult observe. Oxygen resonance fluorescence at 130.4 nm provides a measurement upper atmospheric and exospheric oxygen. More than 500 profiles are constructed using long–exposure time cross–exospheric mode...
Abstract The 14 October 2023 annular solar eclipse was visible from the US Pacific coast to Brazil's east coast. NASA's Global‐scale Observations of Limb and Disk (GOLD) mission observed first synoptic thermospheric temperature changes a geo‐stationary orbit above 47.5°W longitude between 17 20 UT during eclipse. These daytime were derived using GOLD's disk far ultraviolet (FUV) measurements. A significant decrease in temperatures (∼100 K) seen near peak annularity compared day before...
Abstract Geomagnetic storms transfer massive amounts of energy from the sun to geospace. Some that is dissipated in ionosphere as energetic particles precipitate and their atmosphere, creating aurora. We used Time History Events Macroscale Interactions during Substorms (THEMIS) mosaic all‐sky‐imagers across Canada Alaska measure amount flux deposited into via auroral precipitation 2013 March 17 storm. determined time‐dependent percent total contributed by meso‐scale (<500 km wide)...
Abstract. The scientific and societal importance of short-term changes in the thermosphere–ionosphere (T–I) system highlights a need to better understand thermosphere. For collision avoidance, this becomes increasingly important as number low-earth-orbiting satellites increases because geomagnetic activity can cause dramatic, unexpected satellite drag. thermospheric density responsible for drag depend primarily on temperature. However, specification could also be problematic during quiet...
[1] The Cassini Ultraviolet Imaging Spectrograph (UVIS) observed Titan's dayside limb in the extreme ultraviolet (EUV) and far (FUV) on 22 June 2009 from a mean distance of 23 Titan radii. These high-quality observations reveal same EUV FUV emissions arising photoelectron excitation photofragmentation molecular nitrogen (N2) as found Earth. We investigate both these solar driven processes with terrestrial airglow model adapted to find that total predicted radiances for two brightest N2 band...