Hostname: page-component-586b7cd67f-tf8b9 Total loading time: 0 Render date: 2024-11-29T15:09:59.786Z Has data issue: false hasContentIssue false

Magnetic structure of ionizing shock waves Part 3. Normal shocks

Published online by Cambridge University Press:  13 March 2009

B. P. Leonard
Affiliation:
Division of Pure and Applied Sciences, Richmond College, City University of New York, Staten Island, New York

Abstract

Normal ionizing shock waves are considered as a subclass of oblique shocks in which the upstream transverse magnetic field component is zero; i.e. the upstream field is normal to the plane of the shock. Non-trivial (switch-on) normal shocks involve a non-zero downstream transverse field component; magnetically trivial normal shocks are simply gas shocks with an imbedded constant normal magnetic field. As with oblique shocks, switch-on normal ionizing shock waves are plane- polarized, provided the conductivity is a scalar. Ohmic structures are discussed for several values of shock Alfv én number, treating the electric field as a free parameter, as usual. For Alfv én numbers extending from zero to two (for the infinite-Mach-number case), there is always a finite range of E field values. Above two, only the gas shock exists, and this requires a unique electric field value. Because the magnetic field magnitude increases through switch-on shocks, there is no mechanism available for converting magnetic energy into thermal energy, as is the case for oblique or skew shocks. Thus, there is no significant downstream heating above the viscous temperature; and, in some cases, slight downstream cooling may even occur. Expansion shocks are not possible in this geometry. Previous studies are reviewed in the light of structural requirements, and some erroneous results are clarified; in particular, it should be noted that MHD switchon solutions for the pre-ionized case are not imbedded in the family of ionizing switch-on solutions.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1972

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Chu, C. K. & Gross, R. A. 1969 Advances in Plasma Physics, vol. 2. (ed. Simon, A. and Thompson, W. B.), p. 139.Google Scholar
Chu, C. K. & Taussig, B. T. 1967 Phys. Fluids, 10, 249.CrossRefGoogle Scholar
Cowley, M. D. 1967 J. Plasma Phys. 1, 37.CrossRefGoogle Scholar
Leonard, B. P. 1972 a J. Plasma Phys. 7, 177.CrossRefGoogle Scholar
Leonard, B. P. 1972 b J. Plasma Phys. 7, 157.CrossRefGoogle Scholar
Molander, R. C. 1970 Phys. Fluids, 13, 3065.CrossRefGoogle Scholar
Perona, G. E. & Axford, W. I. 1968 Phys. Fluids, 11, 294.CrossRefGoogle Scholar
Taussig, R. T. 1965 Phys. Fluids, 8, 1616.CrossRefGoogle Scholar
Taussig, R. T. 1967 Phys. Fluids, 10, 1145.CrossRefGoogle Scholar