The WIND SPACECRAFT EXPERIMENT

[WIND image (298 Kb)] Image of the WIND Satellite(298 K)

About WIND:

This spacecraft is the first of NASA's Global Geospace Science (GGS) program, which is part of the International Solar-Terrestrial Physics (ISTP) Science Initiative, a collaboration between several countries in Europe, Asia, and North America. The aim of ISTP is to understand the behavior of the solar-terrestrial plasma environment in order to predict how the Earth's atmosphere will respond to changes in solar wind conditions. WIND's objective is to measure the properties of the solar wind before it reaches the Earth.

[Image of WIND's instrumentation (14 Kb)] Schematic of WIND's instrumentation. (14 K)

A more detailed description of WIND is available from ISTP.

About the 3-D Plasma Instruments:

The U.W. Space Physics group is involved with the 3-D particle detectors that will provide unpredecented time resolution of particle distributions in the solar wind and the magnetosphere.

Extensive documentation is available at the 3-D Plasma and Energetic Particle Investigation Home Page, at the U.C. Berkeley Space Science Laboratory. Real-Time Data and Weekly Status Reports are also available.

(The following is lifted verbatim from ISTP's Spacecraft and Instruments Summary, which gives descriptions of numerous ISTP instruments.)

Experiment Overview

The 3-D Plasma and Energetic Particle Analyzer investigation will measure ions and electrons in the interplanetary medium with energies including that of the solar wind and the energetic particle range. It will study the particles upstream of the bow shock in the foreshock region and the transient particles emitted by the Sun during solar particle events following solar flares. This experiment will cover the gap between the energy ranges covered by SWE and EPACT.

Science Objectives

To explore the interplanetary particle population in the thermal and suprathermal energy range, to study the particle acceleration at the Sun, in the interplanetary medium, and upstream from the Earth, to study transport of particles and basic plasma processes in the interplanetary medium, and to measure the particle and plasma input to and output from the Earth's magnetosphere.

Measurement Objectives

To obtain the following measurements:

Description of Instrument

The 3-D PLASMA instrument consists of two sensor packages mounted on small radial booms, and an electronics package mounted inside the spacecraft. One boom-mounted sensor package contains an array of 6 double-ended semiconductor telescopes, each with two or three closely sandwiched silicon detectors to measure ebctrons and ions above 20 keV. One side of each telescope is covered with a thin foil which absorbs ions below 400 keV. On the other side, the incoming electrons below 400 keV are swept away by a magnet so that electrons and ions are cleanly separated. Higher energy electrons (up to ~1 MeV) and ions (up to 11 MeV) are identified by the two double-ended telescopes which have a third detector. The first sensor package also contains a pair of ion electrostatic analyzers (PESA-L and -H) for measuring ion fluxes from ~3 eV to 40 keV. The second sensor package contains a pair of electron electrostatic analyzers (EESA-L and -H) for measuring electron fluxes from ~3 eV to 30 keV, and for making input (from EESA-H) to a fast particle correlator (FPC). The FPC, using also plasma wave data from WAVES as input, measures perturbations to the electron distribution function and studies other wave-particle interactions.

Who's Doing It:

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The WIND Spacecraft Experiment / 5 April 1995 / freeman@geophys.washington.edu