The Search Coil Magnetometer for THEMIS

Roux, A.; Contel, O. Le; Coillot, Christophe; Bouabdellah, Abdel; Porte, B. de la; Alison, Dominique; Ruocco, S.; Vassal, M. C.

doi:10.1007/s11214-008-9455-8

Cited by 211 publications

(184 citation statements)

References 17 publications

(17 reference statements)

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“…The magnetic and electric field data are taken from the magnetometer (FGM) (Auster et al, 2008) and from the Electric Field Instrument (EFI) (Bonnell et al, 2008), respectively. The electric and magnetic field wave spectra were obtained from the EFI and the Search Coil Magnetometer (SCM) (Roux et al, 2008) with frequencies measured from 1 to 4 kHz. If not specially mentioned, we use the geocentric solar magnetospheric (GSM) coordinate system everywhere in the paper.…”

Section: Data Descriptionmentioning

confidence: 99%

Contrasting dynamics of electrons and protons in the near-Earth plasma sheet during dipolarization

et al. 2018

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Abstract. The fortunate location of Cluster and the THEMIS P3 probe in the near-Earth plasma sheet (PS) (at X ∼ −7-−9 R E ) allowed for the multipoint analysis of properties and spectra of electron and proton injections. The injections were observed during dipolarization and substorm current wedge formation associated with braking of multiple bursty bulk flows (BBFs). In the course of dipolarization, a gradual growth of the B Z magnetic field lasted ∼ 13 min and it was comprised of several B Z pulses or dipolarization fronts (DFs) with duration ≤ 1 min. Multipoint observations have shown that the beginning of the increase in suprathermal (> 50 keV) electron fluxes -the injection boundary -was observed in the PS simultaneously with the dipolarization onset and it propagated dawnward along with the onset-related DF. The subsequent dynamics of the energetic electron flux was similar to the dynamics of the magnetic field during the dipolarization. Namely, a gradual linear growth of the electron flux occurred simultaneously with the gradual growth of the B Z field, and it was comprised of multiple short (∼ few minutes) electron injections associated with the B Z pulses. This behavior can be explained by the combined action of local betatron acceleration at the B Z pulses and subsequent gradient drifts of electrons in the flux pile up region through the numerous braking and diverting DFs. The nonadiabatic features occasionally observed in the electron spectra during the injections can be due to the electron interactions with high-frequency electromagnetic or electrostatic fluctuations transiently observed in the course of dipolarization.On the contrary, proton injections were detected only in the vicinity of the strongest B Z pulses. The front thickness of these pulses was less than a gyroradius of thermal protons that ensured the nonadiabatic acceleration of protons. Indeed, during the injections in the energy spectra of protons the pronounced bulge was clearly observed in a finite energy range ∼ 70-90 keV. This feature can be explained by the nonadiabatic resonant acceleration of protons by the bursts of the dawn-dusk electric field associated with the B Z pulses.

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Section: Data Descriptionmentioning

confidence: 99%

Contrasting dynamics of electrons and protons in the near-Earth plasma sheet during dipolarization

et al. 2018

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“…These whistler mode waves can be measured by the Search-Coil Magnetometer (SCM) Roux et al, 2008] and Electric Field Instrument (EFI) . Several waveform bursts, each lasting about 6-8 s, are recorded per day simultaneously from SCM and EFI with a sampling frequency of up to~16 kHz.…”

Section: Themis Data Analysismentioning

confidence: 99%

New evidence for generation mechanisms of discrete and hiss‐like whistler mode waves

Gao

Thorne

et al. 2014

Geophysical Research Letters

103

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Linear theory suggests that whistler mode wave growth rates are proportional to the ratio of hot electron (~1 to 30 keV) density to total electron density (N h /N t ), whereas nonlinear wave theory suggests that an optimum linear growth rate is required to generate rising tone chorus from hiss-like emissions. Using the Time History of Events and Macroscale Interactions during Substorms waveform data collected by three probes over the past~5 years, we investigate the correlation between N h /N t and wave amplitude/wave occurrence rate for rising tone, falling tone, and hiss-like emissions separately. Statistical results show that the rising and falling tones preferentially occur in the region with a limited N h /N t range, whereas both the occurrence rate and wave amplitudes of hiss-like emissions become larger for higher values of N h /N t . Our statistical results not only provide an important clue on the generation mechanism of hiss-like emissions, but also provide supporting experimental evidence for the nonlinear theory of generating rising tone chorus.

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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 Search Coil Magnetometer for THEMIS

Cited by 211 publications

References 17 publications

Contrasting dynamics of electrons and protons in the near-Earth plasma sheet during dipolarization

Contrasting dynamics of electrons and protons in the near-Earth plasma sheet during dipolarization

New evidence for generation mechanisms of discrete and hiss‐like whistler mode waves

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

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