Galactic He 3 above 10 MeV per nucleon and the solar contributions of hydrogen and helium
Interplanetary space He 3 differential energy spectrum in 10-30 MeV range from IMP 4 satellite observations, noting solar contributions
Hsieh, K. C.↗
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The emission and propagation of approximately 40 keV solar electrons
Energetic solar electron emission and cone propagation by IMP satellites, noting relation to proton and relativistic energy events
Lin, R. P.↗
Energetic electrons in the plasma sheet out to 40 R sub E
Energetic electrons in magnetospheric tail plasma sheet, investigating flux time profiles and correlation with local magnetic fields from Imp 3 satellite observation data
Anderson, K. A.↗
Intensities of low-energy cosmic-ray H 2 and He 3 nuclei measured in 1967-1968
Low energy cosmic ray H 2 and He 3 nuclei intensities /1967-1968/ from Pioneer 8 and IMP 4 measurements
Baity, W. H.↗
Long term storage of relativistic particles in the solar corona
Long term storage of relativistic energetic electrons and protons in solar corona from IMP 4 and Pioneer 8 observations related to delayed emission from flares
Holt, S. S.↗
Cosmic-ray H2 from satellite measurements, 1965-1969
Differential energy spectrum of cosmic ray deuterium flux of galactic origin from IMP 5 satellite measurements
Hsieh, K. C.↗
Magnetospheric substorm observations near the neutral sheet
Magnetospheric observations by Imp 3 satellite of energetic electron and magnetotail field variations near neutral sheet as function of substorm time
Akasofu, S.-I.↗
Plasma in the earth's polar magnetosphere
Plasma in dayside polar magnetosphere, analyzing Imp 5 and other earth satellites measurements data
Frank, L. A.↗
Average and unusual locations of the earth's magnetopause and bow shock
Magnetopause and bow shock location from IMP measurements, discussing solar wind momentum flux induced orbit-to-orbit changes in boundary positions
Fairfield, D. H.↗
A study of the flexible body dynamics of the RAE-A satellite
Spacecraft flight data was compared with simulated data computed by the RAE and IMP dynamics simulator computer programs. There was not sufficient data available to provide definitive data on antenna boom position to the Radio Astronomy experimenter. There was, however, enough data to indicate the trend of antenna boom stiffness and temperature gradient. It was possible to obtain a good fit of simulated data to measured spacecraft attitude data when the antenna booms were extended to 450 feet. The value of the RAE-A antenna boom stiffness appears to be significantly less than the preflight ground measured value. It was confirmed that an improved simulation can be obtained by using values of the root angles of the antenna booms and by using an angle of the damper plane of motion, relative to the plane of the antennas, which differed from preflight ground measurements.
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Magnetotail changes in relation to the solar wind magnetic field and magnetospheric substorms
An attempt is made to understand some of the magnetotail dynamics by using simultaneous observations from several satellites: Explorers 33 and 35 in the solar wind, IMP 4 in the near magnetotail (30 RE), ATS 1, and OGO 5 in the magnetosphere. It was observed that in the main lobes of the tail the magnetic field increases slowly when the interplanetary magnetic field turns southward, and can decrease slowly after a substorm. The plasma sheet changes indicate a thinning when the interplanetary magnetic field turns southward and an expansion when it turns northward. When combined with the plasma sheet expansion, which has been observed to follow a substorm, these results allow a schematic view of the relations between the changes in the orientation of the solar wind magnetic field, the substorms, and the changes in the tail parameters to be developed.
Aubry, M. P.↗
The multifarious temporal variations of low energy, relativistic cosmic ray electrons
A detailed examination is made of the intensity variations of 3 - 12 MeV interplanetary electrons. The data used are from the cosmic ray experiment flown on the IMP solar minimum through to the onset of the present solar maximum (i.e., from December 1963 through August 1969). A morphology for the intensity changes is tentatively proposed which includes solar flare-associated events, solar co-rotating increases, Forbush decreases, and quiet-time increases, as well as the long term eleven-year variation. It is contended that the electron component observed both during quiescent times and during quiet-time increases are galactic in origin. The quiet-time increases represent a completely new phenomenon that appears to be unique to the low energy electron population. During a quiet-time increase the electron intensity is enhanced by a factor of 3 to 5 over a period of days, and, in general, these periods anti-correlate with low-energy solar particle events. Qualitatively, their amplitude diminishes with increasing solar activity.
Mcdonald, F. B.↗
New measurements of the galactic radiation spectrum between 200 KHz and 2.6 MHz
The Goddard Space Flight Center radio astronomy experiment aboard the IMP-6 satellite has provided new data on the absolute spectrum of the galactic background radiation at frequencies between 0.2 and 2.6 MHz. The measurements have been obtained both in the terrestrial magnetosphere and in interplanetary space. One of the primary investigations was the measurement of the low frequency component of the galactic radiation. The main sources of error are considered to be the rms noise fluctuations of the receiver, the measurement of the dipole antenna impedance, and in the determination of the noise source used in the preflight calibration of the receiver system. Interstellar models are planned considering the ambient plasma.
Brown, L. W.↗
Solid state ku-band power amplifiers, phase 1
A proposed solid-state K sub u-band power amplifier utilizing a circularly symmetric array of IMPATT diodes mounted in a single radial line power combiner is discussed and its performance predicted. The proposed amplifier configuration consists of a TM sub 030 mode radial line cavity containing 20 IMPATT diodes, with separate input and output ports provided by a ferrite circulator. Conventional IMPATT amplifier techniques preclude the achievement of gain, power output, efficiency, and IMP suppression specifications simultaneously; there fore, several novel techniques with the potential of reducing the intermodulation product level are discussed.
Cohn, M.↗
Direct observations of low-energy solar electrons associated with a type 3 solar radio burst
On 6 April 1971 a solar X-ray flare and a type 3 solar radio noise burst were observed with instrumentation on the eccentric-orbiting satellite IMP 6. The type 3 solar radio noise burst was detected down to a frequency of 31 kHz. A highly anisotropic packet of low-energy solar electron intensities arrived at the satellite approximately 6000 seconds after the onset of the solar flare. This packet of solar electron intensities was observed for 4200 seconds. Maximum differential intensities of the solar electrons were in the energy range of one to several keV. The frequency drift rate of the type 3 radio noise at frequencies below 178 kHz also indicated an average particle speed corresponding to that of a 3-keV electron. The simultaneous observations of these solar electron intensities and of the type 3 solar radio burst are presented, and their interrelationships are explored.
Frank, L. A.↗
Magnetospheric boundaries
The location of the outer boundary of the geomagnetic field, or magnetopause, and the location of the earth's bow shock have been compiled based on data from the first six IMP satellites.
Fairfield, D. H.↗
The coronal transport of the flare associated scatter free electrons
A total of 11 scatter-free electron events from McMath plage region 8905 were observed by IMP 4 during the period from 29 July to 3 August 1967. The transit times and duration of these electron events are examined in detail. The duration of 170- to 1000-keV electrons shows a strong dependence upon the heliolongitude of the associated flare. Typical values of the duration full width at half maximum vary from 4 min at 50 deg W to 12 min at 10 deg and 90 deg W heliolongitudes. In addition, the difference in times at which the maximum intensities of the 22- to 45-keV and 170- to 1000-keV electrons occur is observed to change from 18 min near 50 deg W to 13 min at 10 deg and 90 deg W heliolongitudes. An idealized two-dimensional diffusion model for the transport of these electrons in the solar corona is proposed. The 22- to 45-keV electrons escape promptly from flare site to the feet of the interplanetary magnetic field lines, whereas 170- to 1000-keV electrons suffer slight scattering. The diffusion coefficient for 170- to 1000-keV electrons is estimated to be 3 X 10 to the 18th power sq cm/sec. Finally, a possible relation between the scatter-free and the classical diffusive-type electron events is discussed.
Wang, J. R.↗
Solar wind physics
A double-chambered gas proportional counter was constructed to detect and identify solar wind ions after acceleration by a high voltage power supply. It was determined that the best method of detecting deuterium in the solar wind is to use a tritium target as proposed for IMP H and J. The feasibility of detecting H(+) and He(+) ions of interstellar origin is considered. A program is described to carry out ground-based astronomical observations of faint, diffuse optical emission lines from interstellar gas. Hydrogen and oxygen emission lines from galactic sources were detected and the galactic and geocoronal H alpha and beta lines were clearly resolved.
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