Lunar Electrical Conductivity Profile

Kuckes, A. F.

doi:10.1038/232249a0

Cited by 24 publications

(12 citation statements)

References 4 publications

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“…In the previous sections, various techniques that have been utilized to investigate lunar electrical conductivity were surveyed. Figure 26 shows representative conductivity profiles that have been calculated, including profiles based on Fourier harmonic analysis of day side lunar data in the solar wind [Kuckes, 1971;, profiles based on transient response analysis of night side lunar data in the solar wind , and a profile based on transient response analysis from data measured in the geomagnetic tail .…”

Section: Discussionmentioning

confidence: 99%

“…In the second technique, which we shall call the frequencydependent harmonic response technique, it was assumed that data measured on the day side of the moon could be modeled by the response of an electrically conducting sphere whose induced eddy current fields are totally confined within the sphere by a highly conducting current sheet exterior to the sphere [Sonett et al, 1971a[Sonett et al, , b, 1972Kuckes, 1971;Sill, 1972]. Harmonic analysis involved Fourier analysis of simultaneous swaths of magnetic field data measured external to the moon and on the lunar surface to get a transfer function for lunar response from which an electrical conductivity profile could be calculated.…”

Section: An Iron-rich Layer In the Moon Has Been Considered By Severamentioning

confidence: 99%

“…This technique was first applied by Sonett et al [1971b], who reported a conductivity profile characterized by a large 'spike' with maximum conductivity about 1500 km from the lunar center. Other conductivity profiles have been calculated by using the transfer function, and thus it is shown that the spike profile is not unique but that the day side transfer function can be fitted by simpler two-and three-layer models [Kuckes, 1971;Sill, 1972;Reisz et al, 1972;Phillips, 1972]. In a more recent report, have presented a large class of possible monotonic and current layer order to circumvent this problem, recent analysis has considered lunar eddy current response during times when the moon is in a lobe of the geomagnetic tail, outside the plasma sheet, where plasma interaction effects (asymmetric confinement, remanent field compression, plasma aliamagnetism, etc.)…”

Section: Lunar Day Side Data Analysis: Transient Responsementioning

confidence: 99%

“…Poloidal response theory for a lunar sphere totally confined by a highly conducting plasma was developed by Blank and Sill [1969], Schubert and Schwartz [1969], and Silt and Blank [1970]. S•nce deployment of the Apollo 12 magnetometer in November 1969, electrical conductivity analysis has been developed with two basic approaches: a time-dependent transient response technique [Dyal and Parkin, 1971c;Sill, 1972;] and a frequency-dependent Fourier harmonic technique [Sonett et al, 1971[Sonett et al, b, 1972Kuckes, 1971;Sill, 1972;Hobbs, 1973]. Past analyses have all used magnetometer data recorded at times when global eddy current fields were asymmetrically confined by the solar wind plasma [Reisz et al, 1972;Schubert et al, 1973c;Smith et al, 1973].…”

Section: Introductionmentioning

confidence: 99%

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Magnetism and the interior of the Moon

Dyal

Parkin

Daily

1974

Reviews of Geophysics

200

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During the time period 1961–1972, 11 magnetometers were sent to the moon. The primary purpose of this paper is to review the results of lunar magnetometer data analysis, with emphasis on the lunar interior. Magnetic fields have been measured on the lunar surface at the Apollo 12, 14, 15, and 16 landing sites. The remanent field values at these sites are 38, 103 (maximum), 3, and 327 γ (maximum), respectively. Simultaneous magnetic field and solar plasma pressure measurements show that the Apollo 12 and 16 remanent fields are compressed during times of high plasma dynamic pressure. Apollo 15 and 16 sub‐satellite magnetometers have mapped in detail the fields above portions of the lunar surface and have placed an upper limit of 4.4 × 1013 G cm³ on the global permanent dipole moment. Satellite and surface measurements show strong evidence that the lunar crust is magnetized over much of the lunar globe. Magnetic fields are stronger in highland regions than in mare regions and stronger on the lunar far side than on the near side. The largest magnetic anomaly measured to date is between the craters Van de Graaff and Aitken on the lunar far side. The origin of the lunar remanent field is not yet satisfactorily understood; several source models are presented. Simultaneous data from the Apollo 12 lunar surface magnetometer and the Explorer 35 Ames magnetometer are used to construct a whole moon hysteresis curve from which the global lunar permeability is determined to be µ=1.012±0.006. The corresponding global induced dipole moment is ∼2 × 1018 G cm³ for typical inducing fields of 10−4 G in the lunar environment. From the permeability measurement, lunar free iron abundance is determined to be 2.5±2.0 wt%. Total iron abundance (sum of iron in the ferromagnetic and paramagnetic states) is calculated for two assumed compositional models of the lunar interior. For a free iron/orthopyroxene lunar composition the total iron content is 12.8±1.0 wt%; for a free iron/olivine composition, total iron content is 5.5±1.2 wt%. Other lunar models with a small iron core and with a shallow iron‐rich layer are also discussed in light of the measured global permeability. Global eddy current fields, induced by changes in the magnetic field external to the moon, have been analyzed to calculate lunar electrical conductivity profiles by using several different analytical techniques. From night side transient data, ranges of conductivity profiles have been calculated. At a depth of 250 km into the moon, the conductivity ranges between 1 × 10−4 and 2 × 10−3 mhos/m. Thereafter, conductivity rises with depth and ranges between 2 × 10−3 and 8 × 10−2 mhos/m at 1000 km depth. Harmonic analyses of day side data are similar to night side results except at the greater lunar depths, where harmonic day side profiles show lower conductivities than the night side results do. Transient response analysis has recently been applied to data measured in the lobes of the geomagnetic tail, and thus calculation is allowed of a conductivity profile that increases with...

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Section: Discussionmentioning

confidence: 99%

Section: An Iron-rich Layer In the Moon Has Been Considered By Severamentioning

confidence: 99%

Section: Lunar Day Side Data Analysis: Transient Responsementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Magnetism and the interior of the Moon

Dyal

Parkin

Daily

1974

Reviews of Geophysics

200

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show abstract

“…A thin, collisionless sheath in the solar wind immediately adjacent to the moon contains electrical currents that are driven by the eddy currents within the moon. [Hamilton, 1965]; squares with crosses, Fo•.• [Hamilton, 1965]; circles, Fo• [Hughes, 1955]; crosses, peridotire [Parkhomenko, 1967]; filled circles, pyrosenite [Parkhomenko, 1967] If we accept the conductivity profile proposed by Kuckes [1971], we must explain a sharp increase in conductivity at a depth near 140 km to a value near 6 X 10 -6 mhos/cm. From the data given in Figure 5, the range in temperatures corresponding to a conductivity of 6 X 10 -6 mhos/cm is 600øC to 1150øC for the materials selected.…”

Section: Electrical Conductivity and Temperaturementioning

confidence: 99%