The SWOOPS (Solar Wind Observations Over the Poles of the Sun) experiment has two electrostatic analyzers, one for positive ions and one for electrons. The electron and ion analyzers are separate instruments that operate asynchronously.

'The ISEE-1 and -2 Plasma Wave Investigation' D. A. Gurnett, F. L. Scarf, R. W. Fredricks, and E. J. Smith, IEEE Transactions on Geoscience Electronics, Vol. GE-16, p. 225-230, 1978. The International Sun-Earth Explorer (ISEE) Program consisted of three satellites intended to study the Earth's magnetosphere and the solar wind. ISEE-1 and ISEE-2 were launched on October 22, 1977 into highly elliptical geocentric orbits. The satellites passed through the magnetosphere and into the magnetosheath during each orbit. ISEE-3 was launched on August 12, 1978 and subsequently inserted into a 'halo orbit' about the the libration point situated about 240 earth radii (Re) upstream between the earth and the sun. Plasma passing this point arrives at the Earth about one hour later where it may cause changes that can be observed by ISEE 1 and ISEE-2. These two spacecraft, separated by a variable distance and with similar instrument complements, were intended to resolve the space-time ambiguity associated with measurements by a single spacecraft on thin boundaries which may be in motion such as the bow shock and the magnetopause. ISEE-1 and ISEE-3 were the principal U. S. contributions to the International Magnetospheric Study. ISEE-2 was built and managed by the European Space Agency. In September 1982 ISEE-3 was diverted from its 'halo orbit' to explore the earth's deep tail region through much of 1983 on its way to an encounter with the comet Giacobini Zinner in September 1985. ISEE-1 had a complement of thirteen experiments to measure the waves, fields, plasma, and particles. The University of Iowa Plasma Wave Instrument (PWI) was one of these thirteen. The ISEE-1 plasma waves instrument provided a comprehensive determination of wave characteristics over a broad frequency range, including high-frequency resolution spectrum scans, simultaneous high-time resolution electric and magnetic frequency spectrum measurements, wave normal and Poynting flux measurements, and wide-band waveform measurements. PWI sampled the environment using three electric dipole antennas with lengths of 215, 73.5, and 0.61 meters for electric-field measurements, and a triaxial search coil antenna with three 16-in high permeability mu-metal cores each wound with 10,000 turns of wire and a preamplifier for magnetic-field measurements. The experiment's main electronics consisted of four main elements: 1) a narrow-band sweep frequency receiver, 2) a pair of high time resolution spectrum analyzers, 3) a wave normal analyzer, and 4) an analog waveform receiver (also called a wide-band receiver). These elements could be electrically connected to the six antennas in various combinations in flight. Data for this file originate with an electric antenna and were measured via the Electric Spectrum Analyzer (ESA). The PWI ESA was designed to provide high time resolution spectrum measurements for resolving wave emissions that are bursty or of a nonlinear nature. The ESA was a 20-channel analyzer covering the range from 5.62 Hz to 311 kHz. It had a relatively coarse frequency resolution, with four frequency channels per decade and bandwidths of +/-15 percent up to 10 kHz and +/-7.5 percent for 10 kHz and above. The ESA was nominally intended for electric field measurements, though 2.2 percent of all ESA measurements were made using the Z-axis magnetic search coil. The ISEE spacecraft collected two separate data products with the PWI ESA. 1) A full frequency range 20-channel spectra and 2) a single-channel, rapid-sample series. The 'E_series' variable in this file provides ESA rapid-sample measurements. Full frequency range 20-channel spectra are provided in a companion file set. The rapid-sample series data were collected at 8-times the data rate of the 20-channel spectra, thus there are 32 samples per second in high rate telemetry mode and 4 per second in low-rate mode. Regardless of the telemetry mode, every 16 seconds the rapid sample channel is incremented until reaching the

'The ISEE-1 and -2 Plasma Wave Investigation' D. A. Gurnett, F. L. Scarf, R. W. Fredricks, and E. J. Smith, IEEE Transactions on Geoscience Electronics, Vol. GE-16, p. 225-230, 1978. The International Sun-Earth Explorer (ISEE) Program consisted of three satellites intended to study the Earth's magnetosphere and the solar wind. ISEE-1 and ISEE-2 were launched on October 22, 1977 into highly elliptical geocentric orbits. The satellites passed through the magnetosphere and into the magnetosheath during each orbit. ISEE-3 was launched on August 12, 1978 and subsequently inserted into a 'halo orbit' about the the libration point situated about 240 earth radii (Re) upstream between the earth and the sun. Plasma passing this point arrives at the Earth about one hour later where it may cause changes that can be observed by ISEE 1 and ISEE-2. These two spacecraft, separated by a variable distance and with similar instrument complements, were intended to resolve the space-time ambiguity associated with measurements by a single spacecraft on thin boundaries which may be in motion such as the bow shock and the magnetopause. ISEE-1 and ISEE-3 were the principal U. S. contributions to the International Magnetospheric Study. ISEE-2 was built and managed by the European Space Agency. In September 1982 ISEE-3 was diverted from its 'halo orbit' to explore the earth's deep tail region through much of 1983 on its way to an encounter with the comet Giacobini Zinner in September 1985. ISEE-1 had a complement of thirteen experiments to measure the waves, fields, plasma, and particles. The University of Iowa Plasma Wave Instrument (PWI) was one of these thirteen. The ISEE-1 plasma waves instrument provided a comprehensive determination of wave characteristics over a broad frequency range, including high-frequency resolution spectrum scans, simultaneous high-time resolution electric and magnetic frequency spectrum measurements, wave normal and Poynting flux measurements, and wide-band waveform measurements. PWI sampled the environment using three electric dipole antennas with lengths of 215, 73.5, and 0.61 meters for electric-field measurements, and a triaxial search coil antenna with three 16-in high permeability mu-metal cores each wound with 10,000 turns of wire and a preamplifier for magnetic-field measurements. The experiment's main electronics consisted of four main elements: 1) a narrow-band sweep frequency receiver, 2) a pair of high time resolution spectrum analyzers, 3) a wave normal analyzer, and 4) an analog waveform receiver (also called a wide-band receiver). These elements could be electrically connected to the six antennas in various combinations in flight. Data for this file originate with the spectrum analyzers. The PWI Spectrum Analyzers were designed to provide high time resolution spectrum measurements for resolving wave emissions that are bursty or of a nonlinear nature. The pair consisted of a 20-channel analyzer covering the range from 5.62 Hz to 311 kHz, and a 14-channel analyzer covering the range from 5.62 Hz to 10 kHz. These analyzers have a relatively coarse frequency resolution, with four frequency channels per decade and bandwidths of +/-15 percent up to 10 kHz and +/-7.5 percent for 10 kHz and above. The center frequencies and bandwidths of the 20- and 14-channel analyzers are identical. The 20-channel analyzer was nominally intended for electric field measurements (which extend up to higher frequencies than the magnetic measurements), and the 14-channel analyzer was nominally intended for magnetic field measurements. All channels are sampled simultaneously so that electric-to-magnetic field ratios could be accurately determined. For a detailed description of the Plasma Wave Instrument, the reader is referred to the IEEE Geoscience Electronics reference above. A common acronym for the plasma waves instrument in older documentation is GUM, which stands for for Gurnett Mother. Since this acronym is not easily recognizable

The Ulysses spacecraft was occulted by the Io Plasma Torus (IPT) during its Jupiter encounter on 8 February 1992. The Ulysses dual-frequency radio subsystem used by the Ulysses Solar Corona Experiment (SCE) was utilized to measure the electron content (column density) of the IPT [BIRDETAL1992B]. In the nominal mode for radio-sounding observations [BIRDETAL1992A], both downlinks (S-band: f_s = 2.3 GHz X-band: f_x = 8.4 GHz) are phase coherent with the uplink (S-band: f_u = 2.1 GHz). The dual-frequency radio-sounding technique exploits the dispersive nature of ionized media on the propagation of the two downlinks. The tiny Doppler shift due to plasma moving in and out of the ray path is greater at S-band than at the higher frequency X-band.

SWE is a comprehensive plasma instrument for the WIND spacecraft, see K.W.Ogilvie, et al., Space Sci. Rev., 71, 55-77, 1995. This product provides solar wind proton parameters, including anisotropic temperatures, derived by non-linear fitting of the measurements and with moment techniques. Data reported within this product do not exceed the limits of various parameters listed in the following section. There may be more valid data in the original dataset that requires additional work to interpret but were discarded due to the limits. In particular we have tried to exclude non-solar wind data from these files. We provide the one sigma uncertainty for each parameter produced by the non-linear curve fitting analysis either directly from the fitting or by propagating uncertainties for bulk speeds, flow angles or any other derived parameter. For the non-linear anisotropic proton analysis, a scalar thermal speed is produced by determining parallel and perpendicular temperatures, taking the trace, Tscalar = (2Tperp + Tpara)/3 and converting the result back to a thermal speed. The uncertainties are also propagated through.

The Ulysses spacecraft was occulted by the Io Plasma Torus (IPT) during its Jupiter encounter on 8 February 1992. The Ulysses dual-frequency radio subsystem used by the Ulysses Solar Corona Experiment (SCE) was utilized to measure the electron content (column density) of the IPT. In the nominal mode for radio-sounding observations, both downlinks (S-band: f_s = 2.3 GHz X-band: f_x = 8.4 GHz) are phase coherent with the uplink (S-band: f_u = 2.1 GHz). The dual-frequency radio-sounding technique exploits the dispersive nature of ionized media on the propagation of the two downlinks. The tiny Doppler shift due to plasma moving in and out of the ray path is greater at S-band than at the higher frequency X-band.

'The ISEE-1 and -2 Plasma Wave Investigation' D. A. Gurnett, F. L. Scarf, R. W. Fredricks, and E. J. Smith, IEEE Transactions on Geoscience Electronics, Vol. GE-16, p. 225-230, 1978. The International Sun-Earth Explorer (ISEE) Program consisted of three satellites intended to study the Earth's magnetosphere and the solar wind. ISEE-1 and ISEE-2 were launched on October 22, 1977 into highly elliptical geocentric orbits. The satellites passed through the magnetosphere and into the magnetosheath during each orbit. ISEE-3 was launched on August 12, 1978 and subsequently inserted into a 'halo orbit' about the the libration point situated about 240 earth radii (Re) upstream between the earth and the sun. Plasma passing this point arrives at the Earth about one hour later where it may cause changes that can be observed by ISEE 1 and ISEE-2. These two spacecraft, separated by a variable distance and with similar instrument complements, were intended to resolve the space-time ambiguity associated with measurements by a single spacecraft on thin boundaries which may be in motion such as the bow shock and the magnetopause. ISEE-1 and ISEE-3 were the principal U. S. contributions to the International Magnetospheric Study. ISEE-2 was built and managed by the European Space Agency. In September 1982 ISEE-3 was diverted from its 'halo orbit' to explore the earth's deep tail region through much of 1983 on its way to an encounter with the comet Giacobini Zinner in September 1985. ISEE-1 had a complement of thirteen experiments to measure the waves, fields, plasma, and particles. The University of Iowa Plasma Wave Instrument (PWI) was one of these thirteen. The ISEE-1 plasma waves instrument provided a comprehensive determination of wave characteristics over a broad frequency range, including high-frequency resolution spectrum scans, simultaneous high-time resolution electric and magnetic frequency spectrum measurements, wave normal and Poynting flux measurements, and wide-band waveform measurements. PWI sampled the environment using three electric dipole antennas with lengths of 215, 73.5, and 0.61 meters for electric-field measurements, and a triaxial search coil antenna with three 16-in high permeability mu-metal cores each wound with 10,000 turns of wire and a preamplifier for magnetic-field measurements. The experiment's main electronics consisted of four main elements: 1) a narrow-band sweep frequency receiver, 2) a pair of high time resolution spectrum analyzers, 3) a wave normal analyzer, and 4) an analog waveform receiver (also called a wide-band receiver). These elements could be electrically connected to the six antennas in various combinations in flight. Data for this file originate with an electric antenna and were measured via the Sweep Frequency Receiver (SFR). The narrow-band sweep frequency receiver was intended to provide very high resolution spectrums with low time resolution for analyzing relatively steady narrow- band emissions such as upper hybrid resonance noise, electron plasma oscillations, and electron cyclotron harmonics. The receiver has 32 frequency steps in each of four bands covering the frequency range from approximately 100 Hz to 400 kHz. The frequency steps are logarithmically spaced with a frequency resolution of about 6.5 percent of the center frequency. The dynamic range of the receiver is 100 dB in the lowest three frequency bands, and 80 dB in the highest. Because the time resolution of the SFR is greater than the typical delay times for waves propagating between the two spacecraft, this receiver is only included on ISEE-1. For a detailed description of the Plasma Wave Instrument, the reader is referred to the IEEE Geoscience Electronics reference above. A common acronym for the plasma waves instrument in older documentation is GUM, which stands for for Gurnett Mother. Since this acronym is not easily recognizable by the space physics community and since no official acronym is provided in the instrument

Explanatory Notes: The 2D Electron Angular Distributions included in this Data Set were measured by the Wind/SWE Strahl Detector (see Ogilvie et al., "SWE, a Comprehensive Plasma Instrument for the Wind Spacecraft", Space Sci. Rev., 71, 55, 1995). Each Angular Distribution was measured at a single Electron Energy. The Energy was selected by applying a Voltage between the Electrostatic Analyzer Plates. The Detector sampled 32 Energies between 19 eV and 1238 eV, and during normal Operation would Sweep through these Energies one at a Time with approximately 12 s Cadence. The 12 Anodes of the Instrument are set in a vertical Pattern in a Plane that contains the Spacecraft Spin Axis, spanning a Field of View +/-28° centered around the Ecliptic (with uneven Angular spacing between Anodes). The Wind Spacecraft Spin Axis is set at a Right Angle with the Ecliptic Plane, allowing different Azimuthal Angles to be sampled as the Spacecraft Spins (3 s Spin Period). These Azimuthal Bins have a Fixed Separation of 3.53°. Each Strahl (and Antistrahl) Distribution measured by the Spacecraft consists of a 14 ⨯ 12 Angular Grid of Electron Counts, that was measured at a Fixed Energy during a single Spacecraft Spin. Counts are converted into Physical Units of f(v) (e.g., cm^-6s^3) in the standard Fashion by accounting for the Detector Efficiency and Geometric Factor. The Data Set reported here contains: f_strahl, f_antistrahl, f_strahl_counts, f_antistrahl_counts, phi_strahl, phi_antistrahl, theta, energy.

These data were obtained from the LANL plasma experiment on ICE (Principal Investigator: S.J. Bame assistance from K. Sofaly and S. Kedge). The instrument measures the 2-D electron distribution function in one spacecraft rotation (3 s) once every 24 s, by obtaining 16 evenly spaced energy spectra, each with 15 contiguous levels covering the energy range 8.5 eV to 1140 eV. From these 2-D distributions the density, velocity, and temperature of the electrons are then derived. A 2-D temperature matrix is calculated which is subsequently diagonalized. Then nominally the maximum temperature corresponds to the parallel temperature and the minimum temperature corresponds to the perpendicular temperature. This is done independently of the magnetic field measurements however, the direction of maximum temperature determined in this manner is usually found to be within 15 degrees of the magnetic field direction inferred from the magnetometer measurements. The time resolution is 24 sec from the start of Day 253 (September 10) until Day 255 (September 12), 18:38. At that time the bit rate dropped from 1024 to 512 bps, and the nominal time resolution went to 48 sec.

These data were obtained from the LANL plasma experiment on ICE (Principal Investigator: S.J. Bame assistance from K. Sofaly and S. Kedge). The instrument measures the 2-D electron distribution function in one spacecraft rotation (3 s) once every 24 s, by obtaining 16 evenly spaced energy spectra, each with 15 contiguous levels covering the energy range 8.5 eV to 1140 eV. From these 2-D distributions the density, velocity, and temperature of the electrons are then derived. A 2-D temperature matrix is calculated which is subsequently diagonalized. Then nominally the maximum temperature corresponds to the parallel temperature and the minimum temperature corresponds to the perpendicular temperature. This is done independently of the magnetic field measurements however, the direction of maximum temperature determined in this manner is usually found to be within 15 degrees of the magnetic field direction inferred from the magnetometer measurements. The time resolution is 24 sec from the start of Day 253 (September 10) until Day 255 (September 12), 18:38. At that time the bit rate dropped from 1024 to 512 bps, and the nominal time resolution went to 48 sec.