The THEMIS ESA Plasma Instrument and In-flight Calibration

McFadden, J. P.; Carlson, C. W.; Larson, D. E.; Ludlam, M.; Abiad, R.; Elliott, Ben; Turin, P.; Marckwordt, Mario; Angelopoulos, V.

doi:10.1007/978-0-387-89820-9_13

Cited by 325 publications

(346 citation statements)

References 10 publications

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“…Though their sampling rate is as much as 64 Hz, we use averaged values over 3 s and 5 min. The plasma distributions are calculated by combining Electrostatic Analyzers (ESA) [McFadden et al, 2008a] and Solid State Telescopes (SST) data. See appendix for further details on the plasma moment calculation.…”

Section: Resultsmentioning

confidence: 99%

Structure, force balance, and evolution of incompressible cross-tail current sheet thinning

Saito

Fairfield

et al. 2011

J. Geophys. Res.

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[1] THEMIS five-point observations on April 8, 2009 were used to study thinning of the current sheet in the near-Earth tail that led to the onset of a small substorm. Taking advantage of a fortuitous alignment of the five spacecraft near 2300 LT and 11 R E and within 1.5 R E of the current sheet center, latitudinal gradients are analyzed. A significant latitudinal pressure gradient is present indicating the necessity of a (J × B) z force to maintain the pre-onset equilibrium state. During thinning the total pressure remained approximately constant at all spacecraft rather than increasing. Within the plasma sheet, magnetic field strength increased while plasma pressure decreased due to decreasing temperature. We present a comprehensive explanation for the relationship between the thinning, the stretched structure, and development of intense current density. Our analysis of this event suggests that (1) the thinning in this event is an MHD force-balanced self-evolving process and is not a forced process due to an increased lobe field; (2) the thinning changes flux tube structure in length and curvature but not significantly in volume; (3) the thinning evolves with a change of the radial plasma pressure profile in the near-Earth tail, which is associated with a locally intensified current sheet. The conclusion is that the increased lobe field strength is not the necessary and the primary cause for cross tail current sheet thinning but rather thinning can occur within the plasma sheet as a result of unknown internal processes.

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Section: Resultsmentioning

confidence: 99%

Structure, force balance, and evolution of incompressible cross-tail current sheet thinning

Saito

Fairfield

et al. 2011

J. Geophys. Res.

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“…At this time, ARTEMIS P1 sat just upstream from the Moon, in the undisturbed solar wind. We show a selection of the observations made by the electrostatic analyzer (ESA) [McFadden et al, 2008], fluxgate magnetometer (FGM) [Auster et al, 2008], electric field instrument (EFI) [Bonnell et al, 2008], and search-coil magnetometer (SCM) [Roux et al, 2008] instruments in Figure 1.…”

Section: High-altitude Observationsmentioning

confidence: 99%

Evidence for small‐scale collisionless shocks at the Moon from ARTEMIS

Halekas

Poppe

McFadden

et al. 2014

Geophysical Research Letters

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ARTEMIS observes structures near the Moon that display many properties commonly associated with collisionless shocks, including a discontinuity with downstream compression of magnetic field and density, heating and wave activity, and velocity deflections away from the Moon. The two-probe ARTEMIS measurements show that these features do not exist in the pristine solar wind and thus must result from lunar influences. Discontinuity analyses indicate mass flux and heating across the boundary, with the normal velocity dropping from supermagnetosonic to submagnetosonic across the discontinuity. The shock location with respect to crustal magnetic fields suggests a causal relationship, implying that solar wind protons reflected from crustal fields may produce the observed structures. These observations may indicate some of the smallest shocks in the solar system (in terms of plasma scales), driven by solar wind interaction with magnetic fields on the order of the ion gyroradius and inertial length.

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“…The THEMIS satellite data enable analyzing statistically the spatial distributions of electrons in the region where the previous missions were not able to cover sufficiently. In this study, we use electron data obtained by the electrostatic analyzer (ESA, 7 eV to 26 keV for electrons) [McFadden et al, 2008a] and magnetic field data obtained by the fluxgate magnetometer (FGM) . Omnidirectional electron energy fluxes and magnetic field data are included in the survey mode telemetry, covering most orbits with a measurement cadence of ∼3 s. The analysis period in this study is from August 2007 to August 2009.…”

Section: Instruments and Data Analysismentioning

confidence: 99%

Transport and loss of the inner plasma sheet electrons: THEMIS observations

et al. 2011

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[1] Using the electron data from the Time History of Events and Macroscale Interactions during Substorms (THEMIS) spacecraft measurements from 2007 to 2009, we derived global phase space density (PSD) distributions of plasma sheet electrons (2-100 eV/nT) to examine the transport process of the electrons to the inner magnetosphere and possible loss mechanisms of plasma sheet electrons during the convective transport. The inner boundaries of the electron plasma sheet were determined by the observed global distributions and compared with the Alfvén boundaries that were calculated by the sum of the simple corotation and convection electric field models. This comparison confirms the previous results that the large-scale convection electric field controls the electron transport to the inner magnetosphere. The gradual decrease in PSD is observed from the dawn to the dayside sector, indicating the existence of some loss mechanisms in the morning sector. The loss time scales estimated from the PSD distributions were compared with the theoretical ones based on the quasi-linear diffusion theory using an empirical wave model of whistler mode chorus. We also estimated the required wave amplitudes that can explain the estimated loss time scales. It is shown that whistler mode chorus has a sufficient power to scatter the plasma sheet electrons, and the required wave amplitudes are roughly consistent with the CRRES statistical survey of the chorus wave amplitude. We suggest that the loss of plasma sheet electrons in the morning sector is mainly induced by pitch angle scattering by whistler mode chorus.

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The THEMIS ESA Plasma Instrument and In-flight Calibration

Cited by 325 publications

References 10 publications

Structure, force balance, and evolution of incompressible cross-tail current sheet thinning

Structure, force balance, and evolution of incompressible cross-tail current sheet thinning

Evidence for small‐scale collisionless shocks at the Moon from ARTEMIS

Transport and loss of the inner plasma sheet electrons: THEMIS observations

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