Experimental study of two-dimensional electron vortex dynamics in an applied irrotational shear flow
- Department of Physics, Occidental College, Los Angeles, California 90041 (United States)
An electron column in a modified Malmberg--Penning trap is used to study the behavior of a single two-dimensional vortex in an imposed irrotational shear flow. Phosphor screen images are presented, showing the dispersion of a vortex in a strong shear flow. The images show a variety of phenomena, including the fission of the original vortex, the emission, stretching, and entrainment of filamentary arms, and turbulent diffusion. The vortex lifetime is measured as a function of applied shear, with vortex strength independently adjustable. These data are compared to the predictions of a fluid theory, which correctly identifies the key dimensionless parameter (shear rate/vorticity) and its critical value. The experimental lifetime of a vortex in a strong shear is found to be the same as the dispersion time of a patch of zero vorticity. The lifetime of an unsheared vortex appears to be limited by a slow diffusion that gradually weakens the vortex.
- OSTI ID:
- 6639837
- Journal Information:
- Physics of Plasmas; (United States), Vol. 1:12; ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
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