Comparison of observed plasma and magnetic field structures in the wakes of Mars and Venus

Journal Article · Mon Jul 01 04:00:00 EDT 1991 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/91JA01102· OSTI ID:5191276

Dubinin, E ^[1]; Lundin, R ^[2]; Riedler, W; Schwingenschuh, K ^[3]; Luhmann, J G; Russell, C T ^[4]; Brace, L H ^[5]

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1. Space Research Inst., Moscow (USSR)
2. Swedish Inst. of Space Physics, Kiruna (Sweden)
3. Space Research Inst., Graz (Austria)
4. Univ. of California, Los Angeles (USA)
5. Univ. of Michigan, Ann Arbor (USA)

Plasma and magnetic field observations from the Phobos 2 spacecraft at Mars and the Pioneer Venus orbiter (PVO) at Venus show that there are some notable similarities in the structure of the low-altitude magnetotails at both of these weakly magnetized planets. In particular, it is found that when conditions in the interplanetary medium are steady and the orbit sampling geometry is appropriate, two magnetic tail lobes, with an intervening plasma sheet or central tail ray in the approximate location of the dividing current sheet, are present. This behavior is seen in both the Phobos 2 ASPERA plasma analyzer data and in the PVO Langmuir probe data. In the Phobos 2 data, the tail ray is found to be composed primarily of antisunward streaming oxygen (O{sup +}) plasma which has a bulk velocity consistent with an energy close to that of the upstream solar wind plasma. The PVO Langmuir probe experiment also detected two (or more) additional cold plasma structures flanking the central figure; Phobos 2 data, on the other hand, show a proton plasma boundary layer flanking the central (mostly O{sup +}) tail ray or plasma sheet, with sporadic fluxes or rays of O{sup +} ions. If the latter considered is to be the magnetosheath (solar wind plasma) at the tail boundary, it is mainly the common central tail O{sup +} features that suggest that there are common planetary ion acceleration and magnetotail formation processes at work in the low-altitude wakes of Mars and Venus. On the other hand, an important contribution from picked-up exospheric hydrogen in the wake at Mars cannot be ruled out.

• OSTI ID: 5191276
• Journal Information: Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 96:A7; ISSN 0148-0227; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640107* -- Astrophysics & Cosmology-- Planetary Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ACCELERATION
ATMOSPHERES
BOUNDARY LAYERS
CHARGED PARTICLES
COLD PLASMA
COMPARATIVE EVALUATIONS
DATA
ELECTRIC PROBES
EVALUATION
INFORMATION
INTERACTIONS
INTERPLANETARY MAGNETIC FIELDS
IONIC COMPOSITION
IONS
LANGMUIR PROBE
LAYERS
MAGNETIC FIELDS
MAGNETOSHEATH
MARS PLANET
MORPHOLOGY
OXYGEN IONS
PLANETARY ATMOSPHERES
PLANETS
PLASMA
PROBES
SOLAR ACTIVITY
SOLAR WIND
VENUS PLANET