Extremely Low Frequency Wave Analyzer

Koons, H. C.; Roeder, J. L.; Harbridge, W. B.

doi:10.2514/3.26367

Cited by 4 publications

(2 citation statements)

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“…One of the two primary science investigations on-board the CRRES satellite was the Low Altitude Satellite Studies of Ionospheric Irregularities (LASSII) experiment [Rodriguez, 1992;Johnson and Kierein, 1992], designed to examine natural irregularities in the ionosphere and to make in situ measurements during the lower-altitude chemical release experiments. LASSII consisted of the QIMS [Trzcinski et al, 1992], the pulsed plasma probe (P3) [Baumback et al, 1992], and the extremely low frequency wave analyzer (ELFWA) [Koons et al, 1992]. Figure 1 is a drawing of the CRRES satellite showing the two solar panels, the QIMS sensor and electronics box, and one of the two chemical release canister modules.…”

Section: Experiments Descriptionmentioning

confidence: 99%

Ionization mechanisms in CRRES chemical releases: 1. In situ measurements and model results

Hunton¹,

Wolf²,

Shadid³

1998

J. Geophys. Res.

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Section: Experiments Descriptionmentioning

confidence: 99%

Ionization mechanisms in CRRES chemical releases: 1. In situ measurements and model results

Hunton¹,

Wolf²,

Shadid³

1998

J. Geophys. Res.

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“…The broadband signal (i.e., the total signal in-band from 2 to 125 Hz) is also averaged and recorded each second. A more complete description of the instrument is given by Koons et al [1992]. caused by ELF hiss propagating in the extraordinary mode.…”

Section: Introductionmentioning

confidence: 99%

Observations of ELF fields near the low‐altitude CRRES chemical releases

Koons¹,

Roeder²

1995

J. Geophys. Res.

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The Combined Release and Radiation Effects Satellite (CRRES) performed a series of seven low-altitude chemical releases between September 10, 1990, and August 12, 1991. Immediately following each chemical release, electric and magnetic fields were detected by the extremely low frequency wave analyzer sensors of the Low Altitude Satellite Studies of Ionospheric Irregularities (LASSII) experiment on the spacecraft. The time series and spectra of the two field components are quite similar for each of the releases but vary in detail from release to release. The index of refraction estimated from the ratio of the magnetic field to the electric field is too small by about 2 orders of magnitude for either the right-hand wave or the extraordinary wave modes which are the only propagating electromagnetic modes in the detected band above the O + ion gyrofrequency (-30 Hz). ELF hiss observed at higher altitudes is found to be propagating in the extraordinary wave mode with the correct index of refraction. This confirms that the intensity measurements are being made correctly by the instrument and that an alternative explanation is required for the signals detected following the chemical releases. We show that the waves are primarily electrostatic and that the magnitude of the wave magnetic field is consistent with the transverse magnetic field component of ion acoustic waves. been made with only electric field sensors [Kelley et al., 1974; Koons and Pongratz, 1979; Holmgren et al., 1980; Kelley et al., 1986; Brenning et al., 1991] or with electric field sensors and a low-sensitivity aspect magnetometer for the magnetic field sensors [Whalen et al., 1985; Swenson et al., 1990; Kelley et al., 1991; Bolin and Brenning, 1993].The aspect magnetometers typically measure ultralowfrequency magnetic perturbations caused by macroscopic currents flowing along the magnetic field line. For example, Bolin and Brenning [1993] describe the field observations during the CRIT II barium release as turbulent electric fields from electrostatic instabilities with lower frequency and more coherent oscillations in the magnetic field near the barium ion gyrofrequency. Also, using the magnetic field measurements during this same experiment, Swenson et al.[1990] calculate that a field-aligned current of 11 mA/m 2 is consistent with the observed •300 nT low-frequency magnetic perturbations during the first few tenths of a second after the barium release.In this paper we describe the ELF electric and magnetic fields from the low-altitude CRRES chemical releases detected by the ELFWA sensors on the CRRES spacecraft. Instrument DescriptionThe ELFWA measures single-axis electric field spectra and amplitudes from 2 to 250 Hz and single-axis magnetic field spectra and amplitudes from 2 to 125 Hz. Two antennas, two preamplifiers, and two electronics boxes comprise the instrument.The electric field sensor consists of two spherical probes each 6.35 cm in diameter on booms 190.5 cm long deployed above the spacecraft. The probes are 4.5 m apart. The signals from...

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Long‐term expansion characteristics of CRRES barium release clouds

Hunton¹

1993

Geophysical Research Letters

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A straightforward approach to calculating number densities of barium ions at the satellite position following CRRES low altitude chemical releases is described. The calculation is based on a phenomenological model of the neutral barium cloud which is taken to expand collisionlessly as a gaussian shell. Ion densities are derived by integrating the photoionization rate along a line extending from the spacecraft position forward into the velocity vector and going through the neutral cloud. Model predictions are compared with in‐situ mass spectrometer data, and shown to be in reasonable agreement.

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Extremely Low Frequency Wave Analyzer

Cited by 4 publications

References 1 publication

Ionization mechanisms in CRRES chemical releases: 1. In situ measurements and model results

Ionization mechanisms in CRRES chemical releases: 1. In situ measurements and model results

Observations of ELF fields near the low‐altitude CRRES chemical releases

Long‐term expansion characteristics of CRRES barium release clouds

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