Consider a plasma of finite dimensions in a static magnetic field. Assume that the plasma is in equilibrium (not necessarily thermal equilibrium), and that some external force—say, a static electric field—is applied to the plasma at some angle to the magnetic field. Then, as Professor Allis pointed out, a sheath will form at the plasma boundaries, such that, within the plasma, the resulting space‐charge field will nearly cancel the applied field. If the applied field is suddenly removed, the sheath will collapse, and this will often lead to natural oscillations of the plasma. If there were no magnetic field, and if the plasma boundaries were planes, the oscillations would occur at the plasma frequency. In the presence of a magnetic field, these oscillations can be very complicated because they involve, in addition to the plasma frequency, the cyclotron frequencies of both electrons and ions. Such oscillations are the manifestation of the many degrees of freedom that a plasma in a magnetic field possesses. Clearly, the understanding of such oscillations is of fundamental importance to the understanding of plasmas.
12. S. J. Buchsbaum, Ion Resonance in a Plasma, Proceedings of the International Conference on High Magnetic Fields, Edited by H. Kolm, B. Lax, F. Bitter, and R. Mills (MIT Press, Cambridge, Mass. 1962).
13. U. R. E. Michel and B. Rosenblum, Phys. Rev. Letters 7, 234 (1961).https://doi.org/PRLTAO
14. G. E. Smith, L. C. Hebel, Jr., and S. J. Buchsbaum, Phys. Rev. (.to be published).
15. T. H. Stix, Phys. Rev. 103, 1146 (1957). https://doi.org/PHRVAO T. H. Stix and R. W. Palladino, Phys. Fluids 1, 446 (1958); https://doi.org/PFLDAS W. M. Huoke, F. H. Tenney, M. N. Brennan, H. N. Hill, Jr., and T. H. Stix, Phys. Fluids 4, 1131 (1961).https://doi.org/PFLDAS
More about the Authors
S. J. Buchsbaum.
Bell Telephone Laboratories, Murray Hill, N.J..
Amid growing investment in planetary-scale climate intervention strategies that alter sunlight reflection, global communities deserve inclusive and accountable oversight of research.
Although motivated by the fundamental exploration of the weirdness of the quantum world, the prizewinning experiments have led to a promising branch of quantum computing technology.
As conventional lithium-ion battery technology approaches its theoretical limits, researchers are studying alternative architectures with solid electrolytes.
November 10, 2025 10:22 AM
This Content Appeared In
Volume 15, Number 12
Get PT in your inbox
PT The Week in Physics
A collection of PT's content from the previous week delivered every Monday.
One email per week
PT New Issue Alert
Be notified about the new issue with links to highlights and the full TOC.
One email per month
PT Webinars & White Papers
The latest webinars, white papers and other informational resources.