J. A. Sauvaud
A5007135238- Ionosphere and magnetosphere dynamics
- Solar and Space Plasma Dynamics
- Astro and Planetary Science
- Geomagnetism and Paleomagnetism Studies
- Planetary Science and Exploration
- Earthquake Detection and Analysis
- Plasma Diagnostics and Applications
- Laser-induced spectroscopy and plasma
- Magnetic confinement fusion research
- Space Science and Extraterrestrial Life
- Atmospheric Ozone and Climate
- Geophysics and Gravity Measurements
- Lightning and Electromagnetic Phenomena
- GNSS positioning and interference
- Space Exploration and Technology
- Magnetic Field Sensors Techniques
- Mass Spectrometry Techniques and Applications
- Particle accelerators and beam dynamics
- Atomic and Subatomic Physics Research
- Isotope Analysis in Ecology
- Scientific Research and Discoveries
- Photocathodes and Microchannel Plates
- Spacecraft and Cryogenic Technologies
- Particle Detector Development and Performance
- High voltage insulation and dielectric phenomena
Institut de Recherche en Astrophysique et Planétologie
2016-2025
Centre National de la Recherche Scientifique
2014-2024
Université Toulouse III - Paul Sabatier
2014-2024
Université de Toulouse
2012-2022
Institute for Resource Analysis and Policy
2011-2022
Institute of Space and Astronautical Science
2006-2020
Roche (France)
2000-2017
Laboratoire de Microbiologie et Génétique Moléculaires
2014
Centre d'Etudes Supérieures de la Renaissance
1999-2013
Centre National d'Études Spatiales
2002-2011
The Fast Plasma Investigation (FPI) was developed for flight on the Magnetospheric Multiscale (MMS) mission to measure differential directional flux of magnetospheric electrons and ions with unprecedented time resolution resolve kinetic-scale plasma dynamics. This increased has been accomplished by placing four dual 180-degree top hat spectrometers around periphery each MMS spacecraft. Using electrostatic field-of-view deflection, eight species together provide 4pi-sr with, at worst,...
Abstract. On board the four Cluster spacecraft, Ion Spectrometry (CIS) experiment measures full, three-dimensional ion distribution of major magnetospheric ions (H+, He+, He++, and O+) from thermal energies to about 40 keV/e. The consists two different instruments: a COmposition DIstribution Function analyser (CIS1/CODIF), giving mass per charge composition with medium (22.5°) angular resolution, Hot Analyser (CIS2/HIA), which does not offer resolution but has better (5.6°) that is adequate...
The magnetometer and electron reflectometer investigation (MAG/ER) on the Mars Global Surveyor spacecraft has obtained magnetic field plasma observations throughout near-Mars environment, from beyond influence of to just above surface (at an altitude ∼100 kilometers). solar wind interaction with is in many ways similar that at Venus active comet, is, primarily ionospheric-atmospheric interaction. No significant planetary global scale been detected date (<2 × 10 21 Gauss–cubic centimeter),...
In this paper we study a flow burst event which took place during enhanced geomagnetic activity on July 22, 2001, when Cluster was located in the postmidnight magnetotail. The associated with clear dipolarization ahead of high‐speed part predominantly Earthward directed flow. Based analysis four spacecraft data, found that ∼2000 km thick front moves and dawnward speed ∼77 km/s. plasma before is deflected, consistent localized bubble centered at midnight side being pushed aside by moving...
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 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...
Mars was once wet but is now dry, and the fate of its ancient carbon dioxide atmosphere one biggest puzzles in martian planetology. We have measured current loss rate due to solar wind interaction for different species: Q(O+) = 1.6.10(23) per second 4 grams (g s(-1)), Q(O+2) 1.5.10(23) s(-1) 8 g s(-1), Q(CO+2) 8.10(22) 6 energy range 30 30,000 electron volts charge. These rates can be propagated backward over a period 3.5 billion years, resulting total removal 0.2 millibar few centimeters...
Abstract. Thirty rapid crossings of the magnetotail current sheet by Cluster spacecraft during July-October 2001 at a geocentric distance 19 RE are examined in detail to address structure sheet. We use four-point magnetic field measurements estimate electric density; spatial scale is estimated integration translation velocity calculated from temporal and derivatives. The local normal-related coordinate system for each case defined combining Minimum Variance Analysis (MVA) curlometer...
Fast vertical flapping oscillations of the plasma sheet have been observed by Cluster on September 26, 2001. The motion had speeds exceeding 100 km/s, an amplitude in excess 1 R E and a quasiperiod ∼3 min. current was mostly tilted Y ‐ Z plane (with tilt sometimes 45°). waves properties kink mode propagated toward dusk flank. allowed to probe structure sheet. Three different methods gave consistent evidence bifurcated cross‐tail with about half all concentrated two sheets (each ∼500–1000 km...
A detailed analysis of the ULF noise observed on GEOS magnetic antennas in frequency range ∼0.2'12 Hz has revealed properties structured emissions occurring just above proton gyrofrequency whose existence was reported by Russell et al. (1970) and Gurnett (1976). These waves are vicinity geomagnetic equator at all L values between ∼4 ∼8. They propagate a direction perpendicular to dc field. The consist harmonically related monochromatic emissions. fundamental is generally order local...
Abstract. Using four-point magnetic field measurements by the Cluster spacecraft, we statistically analyze and electric current configurations during rapid crossings of sheet observed in July-October 2001 at geocentric distances 19 RE. The database includes 78 crossings, specially selected to apply multi-point data analysis techniques calculate vector derivatives. Observed bipolar variations jz, often with | jz |>jy, indicate that currents follow kinks sheet. density varies between...
We present a comprehensive observational study of the magnetospheric response to an interplanetary magnetic field (IMF) tangential discontinuity, which first struck postnoon bow shock and magnetopause then swept past prenoon on July 24, 1996. Although unaccompanied by any significant plasma variation, discontinuity interacted with form hot flow anomaly (HFA), was observed Interball‐1 just upstream from shock. Pressures within Earthward HFA were depressed order magnitude, allowed briefly (∼7...
Spacecraft potential measurements by the EFW electric field experiment on Cluster satellites can be used to obtain plasma density estimates in regions barely accessible other type of experiments. Direct calibrations as a function measured difference between spacecraft and probes carried out solar wind, magnetosheath, plasmashere use CIS ion WHISPER electron measurements. The photoelectron characteristic (photoelectrons escaping current balance with collected ambient electrons) calculated...
Magnetic field variations measured onboard the ISEE‐1 spacecraft in tail northern lobe (∼22 R E geocentric distance) during a substorm with multiple onsets are analyzed and simulated using model current sheet. This remote sensing study of cross‐tail sheet shows that associated partial disruption begins near‐earth plasma (∼7 ) expands tailward expansion velocity order 300 km/s. The two consecutive onsets, which occur very active period (AE > 500 nT), correspond to similar tailwards over...
We discuss two phases of the substorm‐associated magnetospheric dynamics in terms particles and fields at synchronous orbit. The first phase corresponds to ‘decreases’ energetic particle flux identified by Erickson Winckler (1973) discussed Walker et al. (1976) (1979). This begins one‐half hour one before substorm onset is characterized (1) a distortion magnetosphere more taillike configuration caused (2) an intensification and/or motion toward earth cross‐tail current its earthward part,...