Hostname: page-component-669899f699-2mbcq Total loading time: 0 Render date: 2025-05-04T18:44:22.643Z Has data issue: false hasContentIssue false
  • English
  • Français

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

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

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