The GSFC cosmic radiation experiment for the Pioneer F/G Jupiter mission

The extremely lightweight, low power design of the cosmic radiation experiment is obtained by using less than 10 percent of the total weight for the mechanical system. Both the baseplate and the top plate are aluminum honeycomb, the side panels are magnesium trusswork, and the inside circuitry is stacked like a sandwich and interleaved with polyester urethane foam for vibration damping. The flight performance of the experimental hardware is excellent

A review of the Jovian magnetosphere based upon Pioneer 10 and 11

Data derived from the plasma, magnetic field, and energetic particle experiments on the December, 1973 and December, 1974 Jupiter encounters are reviewed. A bow shock was discovered on the solar side of the planet, as predicted. However, a smaller magnetic field and larger fluxes of energetic electrons were found than anticipated. A ring current and current sheet in the Jovian plasmasphere are inferred from magnetic field measurements

Radiation damage effects on solid state detectors

Totally depleted silicon diodes are discussed which are used as nuclear particle detectors in investigations of galactic and solar cosmic radiation and trapped radiation. A study of radiation and chemical effects on the diodes was conducted. Work on electron and proton irradiation of surface barrier detectors with thicknesses up to 1 mm was completed, and work on lithium-drifted silicon devices with thicknesses of several millimeters was begun

Flight data systems using LSI P-channel MOSFETS

Continuing development and expansion of a series of P-channel MOSFET circuits in flight data systems is reported. Using hybrid thick film techniques, these circuits evolved into bugs with more than 1000 transistors on a chip. A proposed data system for Helios satellite will have approximately 130 bugs and a semiconductor count of more than 100,000, will weigh less than 1 N and use less than 1.2 W

The Helios solar probes science summaries

The principal results of the Helios investigations through the first five years of the missions are presented

Acceleration of protons at 32 Jovian radii in the outer magnetosphere of jupiter

During the inbound pass of Pioneer 10, a rapid ten-fold increase of the 0.2 to MeV proton flux was observed at 32 Jovian radii (R sub J). The total event lasted for 30 minutes and was made up of a number of superimposed individual events. At the time, the spacecraft was in the outer magnetosphere about 7 R sub J below the magnetic equator. Before and after the event, the proton flux was characteristic of the low flux level normally encountered between crossings of the magnetic equator. Flux changes at different energies were coherent within 1 minute; a time comparable to the time resolution of the data. The angular distributions were highly anisotropic with protons streaming towards Jupiter. A field-aligned dumbbell distribution was observed initially, and a pancake distribution just before the flux decayed to its pre-event value. The alpha particle flux changed as rapidly as the proton flux but peaked at different times. The energetic electron flux behaved differently; it increased gradually throughout the period

Energetic particles in the pre-dawn magnetotail of Jupiter

A detailed account is given of the energetic electron and proton populations as observed with Voyagers 1 and 2 during their passes through the dawn magnetotail of Jupiter. The region between 20 and 150 R sub J is dominated by a thin plasma sheet, where trapped energetic electron and proton fluxes reach their maximum. Proton spectra can be represented by an exponential in rigidity with a characteristic energy of approximately 50 keV. Proton anisotropies were consistent with corotation even at 100 R sub J. A major proton acceleration event as well as several cases of field aligned proton streaming were observed. The flux of 0.4 MeV protons decreases by three orders of magnitude between 30 and 90 R sub J and then remains relatively constant to the magnetopause. Fine structure in the data indicate longitudinal asymmetries with respect to the dipole orientation. Electron spectra in the magnetosheath and interplanetary space are modulated by the Jovian longitude relative to the subsolar point

Energetic protons in the Jovian magnetosphere

The time histories, angular distributions and energy spectra of energetic protons were measured over an energy range extending from 0.2 - 20 MeV for the four passes of Pioneers 10 and 11 through the Jovian magnetosphere. Azimuthal asymmetries appear to dominate with time variations also contributing to the very complex topology. On the inbound P-10 pass the expected corotation anisotropy was not observed in the outer magnetosphere supporting the probable existence of a planetary wind in this region. Near the dawn meredian particle streaming away from the planet begins at about 15 RJ. On both the P-10 inbound and P-11 outbound passes, there are regions where only partial corotation is achieved. In the mid-magnetosphere, field-aligned streaming away from the near-equatorial current sheet region is the most prominent feature. At mid-latitudes in the subsolar regime, the streaming pattern is more chaotic and its magnitude is smaller. Qualitative discussions are presented for a number of possible mechanisms which could produce this streaming

Helios 1 energetic particle observations of the solar gamma ray flare events of 7, 21 June 1980 and 3 June 1982

The observed characteristics of the energetic particles associated with the solar gamma-ray events of 3, 21 June 1980 and 3 June 1982 differ in several important aspects from the typical solar particle increases. They have flat energy spectra, are electron rich and have small precursors increases that begin some hours before the impulsive flare increase

Energetic particle observations of the solar-gamma ray/neutron flare events of 3 Jun 1982 and 21 June 1980 isotopic and chemical composition

Studies of the charge composition of two solar gamma ray/neutron-flare events reveal a striking enrichment of iron relative to oxygen with a smaller enrichment of intermediate nuclei. He/O is also enhanced and moderate amounts of He-3 are detected but there is no evidence for H-2 or H-3