L. Andersson
A5028476423- Planetary Science and Exploration
- Astro and Planetary Science
- Ionosphere and magnetosphere dynamics
- Solar and Space Plasma Dynamics
- Space Science and Extraterrestrial Life
- Geomagnetism and Paleomagnetism Studies
- Earthquake Detection and Analysis
- Laser-induced spectroscopy and plasma
- Space Exploration and Technology
- Geophysics and Gravity Measurements
- Space exploration and regulation
- Scientific Research and Discoveries
- Dust and Plasma Wave Phenomena
- Atmospheric Ozone and Climate
- Magnetic confinement fusion research
- Plasma Diagnostics and Applications
- Spacecraft Design and Technology
- Shoulder Injury and Treatment
- Spacecraft and Cryogenic Technologies
- GNSS positioning and interference
- Magnetic Field Sensors Techniques
- Spaceflight effects on biology
- Electron and X-Ray Spectroscopy Techniques
- Geophysics and Sensor Technology
- Space Satellite Systems and Control
Laboratory for Atmospheric and Space Physics
2016-2025
University of Colorado Boulder
2016-2025
John Wiley & Sons (United States)
2018-2019
University of Colorado System
2014-2019
Charles River Laboratories (Netherlands)
2018-2019
KU Leuven
2011
Swedish Institute of Space Physics
1997-2002
University of Calgary
1998
Johns Hopkins University Applied Physics Laboratory
1998
Johns Hopkins University
1998
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 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)...
Observations obtained by the Freja satellite at altitudes around 1700 km in high‐latitude magnetosphere are used to study ion energization perpendicular geomagnetic field. Investigations of ions, electrons, plasma densities, electric and magnetic wave fields, field‐aligned currents O + heating mechanisms. Three events studied detail, 20 a detailed statistical study. More than 200 classified as belonging one four major types ordered function local time. The most common associated with...
Abstract We present Mars' electron temperature ( T e ) and density n altitude profiles derived from the MAVEN (Mars Atmosphere Volatile EvolutioN) mission deep dip orbits in April 2015, as measured by Langmuir probe instrument. These had periapsides below 130 km at low solar zenith angles. The were above peak during this period. Using a Chapman function fit, we find that scale height projected of are consistent with models previous measurements. is slightly higher than earlier works. For...
Abstract Photochemical escape of atomic oxygen is thought to be one the dominant channels for Martian atmospheric loss today and played a potentially major role in climate evolution. Mars Atmosphere Volatile Evolution Mission (MAVEN) first mission capable measuring, situ, relevant quantities necessary calculate photochemical fluxes. We utilize 18 months data from three MAVEN instruments: Langmuir Probe Waves, Neutral Gas Ion Mass Spectrometer, SupraThermal And Thermal Composition. From these...
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 observations of large‐amplitude (>50 mV/m) electric fields primarily associated with bursty bulk flow events. These reach ~500 mV/m, which are some the largest ( E ) observed in magnetotail. not only has a larger than expected component perpendicular to magnetic field but often an intense parallel component. High time resolution waveforms reveal nonlinear structures such as electron phase‐space holes and double layers, suggest strong field‐aligned currents or beams....
The Mars Atmosphere and Volatile Evolution (MAVEN) mission, during the second of its Deep Dip campaigns, made comprehensive measurements martian thermosphere ionosphere composition, structure, variability at altitudes down to ~130 kilometers in subsolar region. This altitude range contains diffusively separated upper atmosphere just above well-mixed atmosphere, layer peak extreme ultraviolet heating primary reservoir for atmospheric escape. In situ reveal previously unmeasured populations...
Abstract We study the Mars Atmosphere and Volatile Evolution spacecraft observations of Martian planetary ion escape during two time periods: 11 November 2014 to 19 March 2015 4 June 24 October 2015, with focus on understanding seasonal variability in response solar extreme ultraviolet (EUV) flux. organize >6 eV O + data by upstream electric field direction estimate rates through plume tail. To investigate dependence EUV flux, we constrain wind dynamic pressure interplanetary magnetic...
We report direct measurements of parallel electric fields related to particle acceleration in a collisionless space plasma. The field is that monotonic potential ramp localized approximately 10 debye lengths along the magnetic field. Electrons accelerated by are accompanied intense electrostatic waves and nonlinear structures interpreted as electron phase-space holes.
We report the first direct observations of parallel electric fields (${E}_{\ensuremath{\parallel}}$) carried by double layers (DLs) in plasma sheet Earth's magnetosphere. The DL observations, made THEMIS spacecraft, have ${E}_{\ensuremath{\parallel}}$ signals that are analogous to those reported auroral region. DLs observed during bursty bulk flow events, current sheet, and boundary layer, all periods strong magnetic fluctuations. These imply a universal process strongly nonlinear kinetic...
Observations of electron phase-space holes (EHs) in Earth's plasma sheet by the THEMIS satellites include first detection a magnetic perturbation ($\ensuremath{\delta}{B}_{\ensuremath{\parallel}}$) parallel to ambient field (${\mathbit{B}}_{0}$). EHs with detectable $\ensuremath{\delta}{B}_{\ensuremath{\parallel}}$ have several distinguishing features including large electric amplitudes, perpendicular ${\mathbit{B}}_{0}$, high speeds ($\ensuremath{\sim}0.3c$) along and sizes...
Abstract Van Allen Probes observations are presented which demonstrate the presence of nonlinear electric field structures in inner terrestrial magnetosphere (<6 R E ). A range observed, including phase space holes and double layers. These observed over several Earth radii radial distance a wide magnetic local times. They dusk, midnight, dawn sectors, with highest concentration premidnight. Some to coincide dipolarizations increases electron energy flux for energies between 1 keV 30 keV....
Abstract We report Mars Atmosphere and Volatile EvolutioN (MAVEN) observations of electrons, ions, magnetic fields which provide comprehensive demonstration reconnection signatures in the Martian magnetotail. In near‐Mars tail current sheet at X MSO ∼−1.3 R M , trapped electrons with two‐sided loss cones were observed, indicating closed field topology. region, MAVEN observed Hall Marsward bulk flows H + O suggest presence lines tailward from spacecraft. Velocity distribution functions...
Abstract High‐resolution particle and wave measurements taken during an oblique bow shock crossing by the Magnetospheric Multiscale (MMS) mission are analyzed. Two regions of differing magnetic behavior identified within shock, one with active fluctuations laminar interplanetary field topology. A prominent reflected ion population is observed in both regions. The region characterized large‐amplitude (>100 mV/m) electrostatic solitary waves, electron Bernstein acoustic along intermittent...
Abstract The first in situ nightside electron density and temperature profiles at Mars are presented as functions of altitude local time (LT) from the Langmuir Probe Waves (LPW) instrument on board Atmosphere Volatile EvolutioN (MAVEN) mission spacecraft. LPW is able to measure densities low ∼100 , a factor up 10 or greater improvement over previous measurements. Above 200 km, near‐vertical few hundred cubic centimeters were observed for almost all LT, with lowest highest temperatures...
Abstract Mars Express and Atmosphere Volatile Evolution (MAVEN) observations have demonstrated the influence of Mars's spatially variable crustal magnetic fields upon configuration plasma in ionosphere. This furthermore leads to variations ionospheric escape, conceivably part through modification density electron temperature upper In this study, we examine MAVEN Langmuir Probe Waves data, finding a clear correspondence between structure both measured temperatures densities, by first...
Abstract On 26 December 2022 the solar wind density dropped by over an order of magnitude and remained low for about a day. We have utilized in‐situ plasma measurements made Mars Atmosphere Volatile EvolutioN mission to determine how this change affected Mars‐solar interaction. During time period, on inbound orbit segments, MAVEN sampled terminator ionosphere, which switched from magnetized unmagnetized state immediately following minimum in density. The magnetic field amplitude was...
In this article we present electric field, magnetic and charged particle observations from the upward current region of aurora focusing on structure fields at boundary between auroral cavity ionosphere. Over 100 high-resolution measurements that were taken by Fast Auroral Snapshot (FAST) satellite are included in study. The support earlier models zone held quasi-static parallel primary acceleration mechanism. addition to statistical study, several examples direct low-altitude put forth....
Direct measurements of parallel electric fields suggest that they are, in part, self-consistently supported as strong double layers the auroral downward current region. The observed have amplitudes reaching nearly 1 V/m and are confined to a thin layer approximately 10 Debye lengths. structures moving at roughly ion acoustic speed direction accelerated electrons, i.e., anti-earthward. On high-potential side field there is clear signature an electron beam which rapidly plateaus within few...