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arXiv · 1705.09806

Experimental Observation of Electron-Acoustic Wave Propagation in Laboratory Plasma

Satyajit Chowdhury·Subir Biswas·Nikhil Chakrabarti·Rabindranath Pal
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Abstract

In the field of fundamental plasma waves, direct observation of electron-acoustic wave (EAW) propagation in laboratory plasmas remains a challenging problem, mainly because of heavy damping. In the MaPLE device, the wave is observed and seen to propagate with phase velocity $\sim1.8$ times the electron thermal velocity. A small amount of cold, drifting electrons, with moderate bulk to cold temperature ratio ($\approx 2 - 3$), is present in the device. It plays a crucial role in reducing the damping. Our calculation reveals that the drift relaxes the stringent condition on the temperature ratio for wave destabilization. Growth rate becomes positive above a certain drift velocity even if the temperature ratio is moderate. The observed phase velocity agrees well with the theoretical estimate. Experimental realization of the mode may open up a new avenue in EAW research.

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Satyajit Chowdhury, Subir Biswas, Nikhil Chakrabarti, Rabindranath Pal. 2017-05-27. Experimental Observation of Electron-Acoustic Wave Propagation in Laboratory Plasma. https://doi.org/10.1063/1.4985680

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