The MIT Faraday cup experiment on IMP 8 measures
currents from solar wind ions, and from these measurements we calculate
the velocity, density, and temperature of the solar wind. The IMP 8 data
files consist of fine resolution data (approximately 1 minute resolution).
IMP 8 spins with a period of approximately 2.7s. The Faraday
Cup (FC) instrument scans the solar wind distribution stepping through a
contiguous set of energy windows, one step per spacecraft spin. The FC
instrument divides the spin into thirty-two, 11.25 degree angular sectors
and integrates the measured currents over different angular sectors
depending upon the Mode in which the instrument is operating. The border
between two of the 11.25 degree angular sectors lies on the Sun-spacecraft
line.
The FC sensor collector plate is divided into two,
semi-circular halves; the division line is parallel to the spacecraft spin
plane which is approximately parallel to the ecliptic plane. The split
collector allow determination of the bulk plasma flow relative to the spin
plane; North/South angles refer to flows coming from above or below the
spin plane respectively (flows from the South are designated as having a
positive N/S angle).
The bulk flow angle in the spin plane is determined from the
measurements of current vs. rotation angle. The currents telemetered to
the ground are the sums of currents for the two half-collectors ("A" and
"B") and, for the TMS and AQM modes, also the current for the
half-collector "B".
Electrons are measured except for the eight angles near the Sun.
The experiment has two memories only one of which is operating
perfectly. As a result, only every other TMS spectrum is usable, and the
time between spectra is usually twice that that would be expected from the
spacecraft spin rate. The bad half-memory also limits the energy windows
that can be used in the other modes, since they require both memories to
hold the data. On occasion, the data are read out rapidly enough by the
spacecraft to allow repeated use of the good half-memory, and the time
resolution in the TMS is approximately 32 seconds.
Version:2.4.1
The MIT Faraday cup experiment on IMP 8 measures
currents from solar wind ions, and from these measurements we calculate
the velocity, density, and temperature of the solar wind. The IMP 8 data
files consist of fine resolution data (approximately 1 minute resolution).
IMP 8 spins with a period of approximately 2.7s. The Faraday
Cup (FC) instrument scans the solar wind distribution stepping through a
contiguous set of energy windows, one step per spacecraft spin. The FC
instrument divides the spin into thirty-two, 11.25 degree angular sectors
and integrates the measured currents over different angular sectors
depending upon the Mode in which the instrument is operating. The border
between two of the 11.25 degree angular sectors lies on the Sun-spacecraft
line.
The FC sensor collector plate is divided into two,
semi-circular halves; the division line is parallel to the spacecraft spin
plane which is approximately parallel to the ecliptic plane. The split
collector allow determination of the bulk plasma flow relative to the spin
plane; North/South angles refer to flows coming from above or below the
spin plane respectively (flows from the South are designated as having a
positive N/S angle).
The bulk flow angle in the spin plane is determined from the
measurements of current vs. rotation angle. The currents telemetered to
the ground are the sums of currents for the two half-collectors ("A" and
"B") and, for the TMS and AQM modes, also the current for the
half-collector "B".
Electrons are measured except for the eight angles near the Sun.
The experiment has two memories only one of which is operating
perfectly. As a result, only every other TMS spectrum is usable, and the
time between spectra is usually twice that that would be expected from the
spacecraft spin rate. The bad half-memory also limits the energy windows
that can be used in the other modes, since they require both memories to
hold the data. On occasion, the data are read out rapidly enough by the
spacecraft to allow repeated use of the good half-memory, and the time
resolution in the TMS is approximately 32 seconds.
| Role | Person | StartDate | StopDate | Note | |
|---|---|---|---|---|---|
| 1. | PrincipalInvestigator | spase://SMWG/Person/Alan.J.Lazarus | |||
| 2. | TeamMember | spase://SMWG/Person/John.D.Richardson |
Text created by MIT IMP8 plasma team
Web Service to this product using the HAPI interface.
Access to Data via CDPP/AMDA Web application.
(Better, from fits) Proton number density
(Better, from fits) Ion Flow Velocity (aberration corrected)
(Better, from fits) Proton most-probable thermal
speed (aberration corrected). Thermal speed is the most probable thermal
speed (i.e., the square root of [2kT/m(proton)]). To convert thermal speed
to temperature in eV, multiply 0.0052 by the square of the thermal speed;
to convert to temperature [K], multiply the square of the thermal speed by
60.5.
(Best, from fits) Proton East/West flow angle
(aberration corrected). Azimuth is E/W, meaning bulk flow from the East
or the West side of the Sun respectively. Positive azimuth angle means
flow from the West.
(Best, from fits) Proton North/South flow angle
(aberration corrected). Azimuth is N/S, meaning bulk flow from the North
or the South side of the Sun respectively. Positive azimuth angle means
flow from the North.