Spacecraft potential effects on electron moments derived from a perfect plasma detector

Génot, Vincent; Schwartz, S. J.

doi:10.5194/angeo-22-2073-2004

Cited by 17 publications

(30 citation statements)

References 14 publications

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“…In this paper we have demonstrated the implementation of the procedure proposed by Génot and Schwartz (2004). Onboard moments must be corrected because they convolve spacecraft effects such as a non-zero potential and finite energy cut-offs, as well as the effect of numerous calibration defects.…”

Section: Discussionmentioning

confidence: 99%

A corrector for spacecraft calculated electron moments

Schwartz

Génot²,

Moullard

et al. 2005

Ann. Geophys.

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Abstract. We present the application of a numerical method to correct electron moments calculated on-board spacecraft from the effects of potential broadening and energy range truncation. Assuming a shape for the natural distribution of the ambient plasma and employing the scalar approximation, the on-board moments can be represented as non-linear integral functions of the underlying distribution. We have implemented an algorithm which inverts this system successfully over a wide range of parameters for an assumed underlying drifting Maxwellian distribution. The outputs of the solver are the corrected electron plasma temperature T e , density N e and velocity vector V e . We also make an estimation of the temperature anisotropy A of the distribution. We present corrected moment data from Cluster's PEACE experiment for a range of plasma environments and make comparisons with electron and ion data from other Cluster instruments, as well as the equivalent ground-based calculations using full 3-D distribution PEACE telemetry.

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Section: Discussionmentioning

confidence: 99%

A corrector for spacecraft calculated electron moments

Schwartz

Génot²,

Moullard

et al. 2005

Ann. Geophys.

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“…The RPC-IES electron spectra are affected by the presence of this negatively charged spacecraft potential. Applying Liouville's theorem to the close environment of the spacecraft, the phase space density f e (r, v) is conserved along the electron's trajectory (Génot & Schwartz 2004), that is, its Lagrangian derivative: dfe dt = 0. The cometocentric distance r 0 of Rosetta of 10-20 km is significantly larger than the extent of the charged cloud around the spacecraft of a few metres (see Section 3.5).…”

Section: Rpc-ies Electron-impact Ionization Frequencymentioning

confidence: 99%

Ionospheric plasma of comet 67P probed byRosettaat 3 au from the Sun

Galand

Héritier

Odelstad

et al. 2016

Mon. Not. R. Astron. Soc.

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170

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We propose to identify the main sources of ionization of the plasma in the coma of comet 67P/Churyumov-Gerasimenko at different locations in the coma and to quantify their relative importance, for the first time, for close cometocentric distances (<20 km) and large heliocentric distances (>3 au). The ionospheric model proposed is used as an organizing element of a multi-instrument data set from the Rosetta Plasma Consortium (RPC) plasma and particle sensors, from the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis and from the Microwave Instrument on the Rosetta Orbiter, all on board the ESA/Rosetta spacecraft. The calculated ionospheric density driven by Rosetta observations is compared to the RPC-Langmuir Probe and RPC-Mutual Impedance Probe electron density. The main cometary plasma sources identified are photoionization of solar extreme ultraviolet (EUV) radiation and energetic electron-impact ionization. Over the northern, summer hemisphere, the solar EUV radiation is found to drive the electron density -with occasional periods when energetic electrons are also significant. Over the southern, winter hemisphere, photoionization alone cannot explain the observed electron density, which reaches sometimes higher values than over the summer hemisphere; electron-impact ionization has to be taken into account. The bulk of the electron population is warm with temperature of the order of 7-10 eV. For increased neutral densities, we show evidence of partial energy degradation of the hot electron energy tail and cooling of the full electron population.

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“…Onboard particle distribution moments (or moments calculated from telemetered particle distributions) can suffer from inaccuracies due to spacecraft charging [e.g., Génot and Schwartz, 2004;Geach et al, 2005;Davis et al, 2008], multiple species [e.g., Paschmann and Daly, 1998], multiple components [e.g., Wüest et al, 2007], and limited energy ranges (e.g., V Ti ≳ V bulk ). In the following we discuss how we accounted for these potential inaccuracies when examining moments of the velocity distribution functions.…”

Section: Appendix C: Removal Of Secondary Ionsmentioning

confidence: 99%

Quantified energy dissipation rates in the terrestrial bow shock: 1. Analysis techniques and methodology

et al. 2014

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Key Points:• High-frequency electric fields are much larger than quasi-static fields • They produce more energy dissipation than the quasi-static fields • Most energy dissipation pathways end with wave-particle interactions AbstractWe present a detailed outline and discussion of the analysis techniques used to compare the relevance of different energy dissipation mechanisms at collisionless shock waves. We show that the low-frequency, quasi-static fields contribute less to ohmic energy dissipation, (−j ⋅ E), than their high-frequency counterparts. In fact, we found that high-frequency, large-amplitude (>100 mV/m and/or >1 nT) waves are ubiquitous in the transition region of collisionless shocks. We quantitatively show that their fields, through wave-particle interactions, cause enough energy dissipation to regulate the global structure of collisionless shocks. The purpose of this paper, part one of two, is to outline and describe in detail the background, analysis techniques, and theoretical motivation for our new results presented in the companion paper. The companion paper presents the results of our quantitative energy dissipation rate estimates and discusses the implications. Together, the two manuscripts present the first study quantifying the contribution that high-frequency waves provide, through wave-particle interactions, to the total energy dissipation budget of collisionless shock waves.

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Spacecraft potential effects on electron moments derived from a perfect plasma detector

Cited by 17 publications

References 14 publications

A corrector for spacecraft calculated electron moments

A corrector for spacecraft calculated electron moments

Ionospheric plasma of comet 67P probed byRosettaat 3 au from the Sun

Quantified energy dissipation rates in the terrestrial bow shock: 1. Analysis techniques and methodology

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