The retarding‐potential analyzer on Atmosphere Explorer

Abstract

A planar retarding‐potential analyzer will be included in each of the Atmosphere Explorer (AE) payloads. The primary functions of the instrument are to supply ion‐temperature and ion‐concentration data, which it will do at least once every 40 km of flight path in the region of interest with an expected accuracy of better than 2%. In addition, the instrument will determine ion‐drift velocities and energy spectra of both the thermal and suprathermal electrons. During eclipse, negative‐ion concentrations greater than 0.3 cm−3 can be detected, though the normal positive‐ion sensitivity is approximately 1.5 ions cm−3. Changes in the ion concentration along the flight path greater than 0.1% can be monitored with a spatial resolution of less than 40 m.

DE 2 observations of morningside and eveningside plasma density depletions in the equatorial ionosphere

“…We present data from the vector electric field instrument (VEFI) [Maynard et al, 1981], the Langmuir probe (LANG) [Krehbiel et al, 1981], and the ion drift meter (IDM) [Heelis et al, 1981]. We also studied magnetic field fluctuations during depletion encounters by using data from the magnetometer [Farthing et al, 1981] on board the satellite.…”

“…In this paper we adopt a fixed coordinate system, where x points southward, y points radially upward, and z points westward. This is regardless of whether the satellite was traversing the equator from the north or from the south and regardless of its rotations every The DE 2 measured complete three-dimensional ion drift velocity by using two separate instruments: the retarding potential analyzer (RPA) [Hanson et al, 1981] measured the velocity component parallel to the velocity vector of the spacecraft (Vx), and the IDM measured ion drift components perpendicular to the velocity vector of the spacecraft (Vy and Vz). The velocity range of IDM was :k4000 m/s with an accuracy of :k50 m/s.…”

The retarding potential analyzer aboard the satellite TAIYO.

“…The measurements of the plasma parameter by the RPA have been carried out with many satellites (see for example HANSON et al, 1970HANSON et al, , 1973SPENNER et al, 1974) and RDA'S may be utilized more and more in the future for these measurements.…”

High Power Ion Cyclotron Heating in the VASIMR Engine

“…Available plasma diagnostics include a triple probe, 32 and 70 GHz density interferometers, a bolometer, a television monitor, an H-α photometer, a spectrometer, neutral gas pressure and flow measurements, several gridded energy analyzers (retarding potential analyzer or RPA) 3,8,47,48,49,50,51,52,53 , a momentum flux probe, an emission probe, a directional, steerable RPA and other diagnostics 54 . Reciprocating Langmuir density interferometer are the primary plasma diagnostics.…”