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Summary-Introduction: Collision-Free Plasmas(*)

Published online by Cambridge University Press:  19 March 2018

H. E. Petschek
H. E. Petschek*
Affiliation:
Avco-Everett Research Laboratory - Everett, Mass.

Extract

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In many cases, the outer atmosphere or corona regions of stars are not dominated by the ordinary process of collisions between ions. Very roughly, collision-free phenomena become of interest when the mean free path for interparticle collisions is larger than the region of space being considered. For solar corona conditions, if we consider a density of 107 particles per cubic centimeter and a typical particle velocity of 500 kilometer per second, the mean free path is a few times the solar diameter. At the same velocity for a density of 100 particles per cubic centimeter, corresponding to the interplanetary density, the mean free path would be a thousand astronomical units. Since in both of these regions, we are interested in smaller dimensions, it is of interest to consider the properties of a plasma in which collisions are very rare.

Type
Part IV. Considerations on Localized Velocity Fields in Stellar Atmospheres: Prototype — The Solar Atmosphere
Information
Symposium - International Astronomical Union , Volume 12: Aerodynamic Phenomena in Stellar Atmospheres , 1960 , pp. 448 - 458
Copyright
Copyright © Italian physical society 1960 

References

[1] Petschek, H. E., Rev. Mod. Phys. , 30, 966 (1958).CrossRefGoogle Scholar
[2] Colgate, S. A., Ferguson, J. P. and Furth, H. P., Proceedings of the Second International Conference on Peaceful Uses of Atomic Energy , 32, 129 (1958).Google Scholar
[3] Fishman, F. J., Kantrowitz, A. R. and Petschek, H. E., Rev. Mod. Phys. 32, 959 (Oct. 1960).Google Scholar
[4] Sherman, F. S., NACA TN 3298, July 1955; Mott-Smith, H. M., Phys. Rev. , 82, 885 (1951).Google Scholar
[5] The suggestion that instabilities would be important in a shock wave in the absence of a magnetic field was first made by Kahn, F. D. (Gas Dynamics of Cosmic Clouds , New York, 1955, chap. 20, p. 115) and discussed somewhat further by E. N. Parker: Astrophys. J., 129, 217 (1959).Google Scholar
[6] A more detailed account of this theory is found in ref. [3].Google Scholar
[7] Patrick, R. M., Phys. of Fluids , 2, 589 (1959) and 3, 321 (1960).Google Scholar
[8] Böhm, K., in The Characteristics of Electrical Discharges in Magnetic Fields , edited by Guthrie, A. and Wakerling, M. K. (New York, 1949), chap. 2, Sect. 5.Google Scholar
[9] Buneman, O., Phys. Rev. , 115, 503 (1959).Google Scholar
[10] Spitzer, L., Phys. of Fluids , 3, 659 (1969).Google Scholar
[11] A more detailed account of this theory is presently being prepared for publication.Google Scholar