Solar-wind and interplanetary electron measurements on the Apollo 15 subsatellite

Anderson, K. A.; Chase, L. M.; Lin, R. P.; McCoy, J. E.; McGuire, R. E.

doi:10.1029/ja077i025p04611

Cited by 31 publications

(14 citation statements)

References 9 publications

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“…While the lunar plasma environment was monitored by the lunar orbiters and landers in 1960∼70s [ Lyon et al , 1967; Colburn et al , 1967; Anderson et al , 1972; Howe et al , 1974; Neugebauer et al , 1972; Clay et al , 1972; Hills et al , 1972], understanding it from the plasma physics point of view via three‐dimensional particle distribution function data was difficult. Most of the subsequent lunar missions were dedicated to the global mapping of the lunar surface [ Nozette et al , 1994; Binder , 1998; Foing et al , 2006].…”

Section: Introductionmentioning

confidence: 99%

Solar wind proton reflection at the lunar surface: Low energy ion measurement by MAP‐PACE onboard SELENE (KAGUYA)

Saito¹,

Yokota²,

Tanaka³

et al. 2008

Geophysical Research Letters

192

182

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Interaction between the solar wind and objects in the solar system varies largely according to the settings, such as the existence of a global intrinsic magnetic field and/or thick atmosphere. The Moon's case is characterized by the absence of both of them. Low energy ion measurements on the lunar orbit is realized more than 30 years after the Apollo period by low energy charged particle analyzers MAP‐PACE on board SELENE(KAGUYA). MAP‐PACE ion sensors have found that 0.1%∼1% of the solar wind protons are reflected back from the Moon instead of being absorbed by the lunar surface. Some of the reflected ions are accelerated above solar wind energy as they are picked‐up by the solar wind convection electric field. The proton reflection that we have newly discovered around the Moon should be a universal process that characterizes the environment of an airless body.

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Section: Introductionmentioning

confidence: 99%

Solar wind proton reflection at the lunar surface: Low energy ion measurement by MAP‐PACE onboard SELENE (KAGUYA)

Saito¹,

Yokota²,

Tanaka³

et al. 2008

Geophysical Research Letters

192

182

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“…Prior to the Explorer 35 and Apollo missions the commonly held view was that the moon was physically inert and devoid of a global magnetic field. This proved to be partially the case; the moon is a 'bare' object aside from the still enigmatic local and regional fossil magnetic fields $onett andMihalov, 1972, Coleman andAnderson et al, 1972;Sharp et al, 1973;Russell et al, 1974aRussell et al, , 1977Hood, 1981]. However, the electromagnetic response of the moon to the solar wind's electromagnetic field is nonvanishing, as expected of a conducting object in a time-varying magnetic field, and is due to the induction of eddy currents in the lunar interior [Blank and Sill, 1969;Schubert and Schwartz, 1969;$onett et al, 1971a].…”

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confidence: 99%

Electromagnetic induction in the Moon

Sonett¹

1982

Reviews of Geophysics

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Except for a boundary layer of uncertain properties the moon constitutes a rigid (nonhydromagnetic) but electrically conducting target to the solar wind when unscreened by the earth's magnetosphere. At frequencies below 3 mHz, observed in the rest frame of the moon, fluctuations of the interplanetary and the geomagnetic tail fields excite eddy currents which penetrate deeper than half the lunar radius. At long wavelength (λ ≫ rM, where rM is the lunar radius) a time‐varying magnetic dipole is induced. Shorter wavelengths excite correspondingly higher‐order magnetic multipoles, but primarily in the outer parts of the moon because of skin depth limitations. The lunar response reaches a peak as frequency increases, diminishing with further increase in frequency. This is interpreted as evidence for the presence of the magnetic quadrupole moment. In the solar wind and magnetosheath the transverse electric mode in the moon is not accompanied by the corresponding transverse magnetic mode, since a bow shock wave is not detected. The latter is probably damped by the nonconducting lunar crust, though the moon is still polarized electrically. It is marginally possible that transient bow wave phenomena appear at times, but because of the high dynamic pressure of the solar wind and magnetosheath, most induced fields are confined to the lunar interior and perhaps the boundary layer. Furthermore, a theorem by Herbert et al. (1976) seems to preclude time‐variable induced magnetospheres. Magnetometer measurements of induction using Explorer and Apollo instruments are reviewed, from both the harmonic and the transient standpoint, and the resulting determination of internal bulk electrical conductivity is discussed. Estimates of both internal temperature and metallized core radius maxima are examined. The closeness of the estimated temperature to the Ringwood‐Essene solidus at 150‐ to 250‐km depth may be indicative of a layer of enhanced conductivity in lieu of high temperature. If so, this suggests a reduction in temperature, bringing the temperature into coincidence with other selenophysical parameters. A reduced core radius estimate with a one‐sigma upper limit of 360 km is reported. Application of inverse theory resolution tests has not been made pending completion of current work involving autoregressive models in attempting to isolate the angular spectrum of real or apparent incident wave normals, upon which the quadrupole response depends. This is also aimed at bypassing current limitations imposed by data gap convolution, data digitization noise, and noise thought to be generated by the interaction of the solar wind with local and regional permanent fields on the lunar surface. Because of length limitations, discussion of lunar electrodynamics has been restricted to the problem of induction, with accompanying subjects such as the flow field and regional electric fields on the moon mentioned only as required. A fuller treatment should include these matters. The review closes prior to ongoing work on high‐frequency induction ...

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“…By suitable subtraction of the fluxes observed in the two telescopes, electron and proton fluxes could be identified and measured. Details of this arrangement are given in Anderson et al (1972).…”

Section: Methodsmentioning

confidence: 99%

“…The ~6 and ~ 14 keV detectors were surrounded by plastic anti coincidence jacket to reject penetrating particles and thereby reduce the background. Further details are contained in Anderson et al (1972).…”

Section: Methodsmentioning

confidence: 99%

Acceleration, Containment, and Emission of Very Low Energy Solar Flare Particles

Lin

McGuire

Anderson

1974

Symp. - Int. Astron. Union

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Abstract. We present the first observations of protons down to 44 keV and electrons down to <, 2 keV emitted in an impulsive solar particle event. The observations are from the Apollo 15 Subsatellite during a flare event which began on September 1, 1971. We obtain a lower limit estimate of the energy contained in £0.05 MeV protons in the flare. The effects of adiabatic deceleration in the interplanetary medium and dE/dx energy loss in the corona are discussed. We conclude that energetic protons may constitute a major energy release in large solar flares.

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Solar-wind and interplanetary electron measurements on the Apollo 15 subsatellite

Cited by 31 publications

References 9 publications

Solar wind proton reflection at the lunar surface: Low energy ion measurement by MAP‐PACE onboard SELENE (KAGUYA)

Solar wind proton reflection at the lunar surface: Low energy ion measurement by MAP‐PACE onboard SELENE (KAGUYA)

Electromagnetic induction in the Moon

Acceleration, Containment, and Emission of Very Low Energy Solar Flare Particles

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