The quiet corona: Temperature and temperature gradient

Bame, S. J.; Asbridge, J. R.; Feldman, W. C.; Kearney, P. D.

doi:10.1007/bf00156963

Cited by 59 publications

(24 citation statements)

References 33 publications

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“…The E/q spectra in Fig. 13 are of typical O-Si-Fe type and in good agreement with the spectra for the cold, low speed, solar wind given by BAME et al (1970, 1974, 1975, 1979), and ZASTENKER and YERMOLAEv (1981. In our experiments, ions heavier than He++ are also found in the E/q spectra in low speed regions, as indicated by the arrows in Fig.…”

Section: Heavy Ionssupporting

confidence: 79%

Observations of solar wind ions by the interplanetary spacecraft Suisei (PLANET-A).

Mukai¹,

Miyake²,

Terasawa³

et al. 1987

J. geomagn. geoelec

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Overview of the solar wind ion measurements which were carried out by the Japanese interplanetary spacecraft Suisei (PLANET-A) is presented. The instrumentation and results obtained from the initial two-month observations are described.(1) The experiment has been successful in resolving solar wind ions into H+, He++, and, sometimes, other minor constituents, such as 0+6, Si+' , Si+8, and iron groups. These heavy ions, which are considered to contain information on the solar corona, have been identified clearly in the low-speed region. (2) The typical corotating structure is observed during two solar rotations near the sunspot minimum . (3) Velocity fluctuations which are interpreted to be Alfvenic fluctuations are observed in high speed streams. (4) It is also found that the flow vector of the solar wind is significantly deflected westwards in the region of increasing velocity, as a result of pressure gradient caused by stream interaction. (5) Anisotropic distributions of protons which may be related to the local magnetic field are also observed.

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Section: Heavy Ionssupporting

confidence: 79%

Observations of solar wind ions by the interplanetary spacecraft Suisei (PLANET-A).

Mukai¹,

Miyake²,

Terasawa³

et al. 1987

J. geomagn. geoelec

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“…8.21 taken from [8.46] for two situations, with (A), and without (B), a ten-percent abundance of alpha particles. Right-hand polarized magnetosonic waves at sufficient power (energy densities at a reasonable fraction of the required beam kinetic-energy density in 86 the solar wind frame) may be able to produce fast protons or alpha particles streaming at the local Alfven speed relative to the core protons [8.188]. A serious drawback in the numerical calculations published so far is the assumption of drifting bi-Maxwellian model distributions and the resulting insufficient flexibility in the shape of these velocity distributions.…”

Section: Regulation Of the Electromagnetic Ion-beam Instabilitymentioning

confidence: 99%

Kinetic Physics of the Solar Wind Plasma

Marsch¹

1991

Physics and Chemistry in Space

190

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“…Near the sun we have used the measurements and arguments of Bame et al (1974), who suggest that T a r-2f7 near the base of the corona. We have used the e results of Ogilvie and Scudder (1977) using data between 0.45 and 0.85 AU that Te , thermal, varies like r 0.3 and the results of Gringauz and Verigin (1975) for l < r `C 1.5 AU and an asymptotic adiabatic behavior at large distances (> 10 AU).…”

Section: Tthermaln'mentioning

confidence: 99%

A theory of local and global processes which affect solar wind electrons, 1. The origin of typical 1 AU velocity distribution functions—Steady state theory

Scudder¹,

Olbert²

1979

J. Geophys. Res.

213

103

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A new detailed first principle kinetic theory for electrons is presented which is neither a classical fluid treatment nor an expospheric calculation. This new theory illustrates the global and local properties of the solar wind expansion that shape the observed features of the electron distribution function fe, such as its bifurcation, its skewness, and the ‘differential’ temperatures of the thermal and suprathermal subpopulations. Our approach starts with the Boltzmann equation and retains the effects of Coulomb collisions via a Krook collision operator without recourse to wave‐particle effects. We conclude that Coulomb collisions determine the population and shape of fe in both the thermal (E kT) energy regimes. We find that electrons with E >7kT constitute a special subpopulation of the suprathermals, insofar as Coulomb collisions are concerned; these we call ‘extrathermals.’ The electrons in the thermal portion of fe have undergone ∼10‐20 Coulomb collisions for cumulative momentum transfer en route to the observer at 1 AU; this population is thus more removed from the properties of coronal electrons than the suprathermal population. This latter group retains a strong memory of coronal conditions, since they have undergone only a few momentum transfer collisions. The thermal population is most nearly in collisional contact with the local dynamics (compressions, rarefactions, etc.) of the solar wind. The suprathermal portion of fe is determined by Coulomb collisional interactions with the distribution of solar wind material on radial scale of the heliopause itself. In this respect the suprathermal portion of fe is found to be responsive to the consequences of the global dynamics of the solar wind expansion. We find that this subpopulation is an attenuated vestige of collisional populations deep in the corona (1.03–10 Rs) which has been redistributed via Coulomb multiple pitch angle scattering on magnetically open field lines. The suprathermal particles moving toward the sun are computed to be observed as a result of Coulomb‐collision‐induced backscattering at larger (1–10 AU) heliocentric distances than that of the observer. Based on this theoretical picture, quantitative estimates for the partition of thermal and suprathermal phase density, the break in the velocity distribution, and the magnitude of the skewness (heat flux density) agree well with those typically observed near 1 AU. These calculations predict that the extrathermal fraction of the phase density, the extrathermal temperature, and the net heat flux density carried by electrons should be anticorrelated with the local bulk speed in quasi‐steady‐state flows and that the radial variation of extrathermal temperature inside 1 AU should be essentially independent of heliocentric distance. Our work also shows that the observation of suprathermal particles cannot be taken as a priori evidence for in situ wave particle interaction(s), since we can theoretically calculate a suprathermal population of solar wind electrons at 1 AU b...

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The quiet corona: Temperature and temperature gradient

Cited by 59 publications

References 33 publications

Observations of solar wind ions by the interplanetary spacecraft Suisei (PLANET-A).

Observations of solar wind ions by the interplanetary spacecraft Suisei (PLANET-A).

Kinetic Physics of the Solar Wind Plasma

A theory of local and global processes which affect solar wind electrons, 1. The origin of typical 1 AU velocity distribution functions—Steady state theory

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