Public Release: 

Intense microwave pulse ionizes its own channel through plasma

More than 30 years ago, researchers theoretically predicted the ionization-induced channeling of an intense microwave beam propagating through a neutral gas (>103 Pa) -- and now it's finally been observed experimentally

American Institute of Physics

WASHINGTON, D.C., October 9, 2018 -- Breakthrough new research shows that ionization-induced self-channeling of a microwave beam can be achieved at a significantly lower power of the microwave beam and gas pressure for radially nonuniform plasma with minimal on-axis density than in the case of plasma formed as the result of gas ionization.

In the journal Physics of Plasmas, from AIP Publishing, Israel Institute of Technology researchers report observing this effect for the first time and studying it in detail in a plasma preliminarily formed by a radiofrequency discharge, in a low-pressure gas (<150 Pa). They were able to do this by using analytical modeling and numerical particle-in-cell simulations, and their work centers on the concept of the nonlinear effect on plasma and magnetic wave interaction.

"Ionization-induced plasma self-channeling is the foundation for microwave plasma wakefield research," said lead author Yang Cao. "A plasma wakefield is a wave generated by particles traveling through a plasma. And a microwave plasma wakefield experiment could give us information about laser wakefield research that's extremely difficult to obtain due to the short time (femtosecond) and geometry scale involved."

This work is significant because microwaves will always diverge, unlike lasers that can be trapped within optical fibers. "In this [way], a self-induced 'microwave fiber' is created that may help the microwave propagate a much longer distance," Cao said.

In the future, the microwave ionization-induced self-channeling effect could be used for further exploring the microwave plasma wakefield or, since it's a form of directed energy, it may also find military applications as a directed-energy weapon.

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The article "Self-channeling of a powerful microwave beam in a preliminary formed plasma" is authored by Yang Cao, John Leopold, Yury P. Bliokh, and Yakov E. Krasik. It appears in the journal Physics of Plasmas on October 2, 2018 (DOI: 10.1063/1.5051226). The article can be accessed at: https://aip.scitation.org/doi/10.1063/1.5051226.

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Physics of Plasmas published by AIP Publishing in cooperation with the APS Division of Plasma Physics, is committed to the publication of original research in all areas of experimental and theoretical plasma physics. See https://aip.scitation.org/journal/php.

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