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Title: General Cause of Sheath Instability Identified for Low Collisionality Plasma in Devices with Secondary Electron Emission

Technical Report ·
DOI:https://doi.org/10.2172/1062660· OSTI ID:1062660

A condition for sheath instability due to secondary electron emission (SEE) is derived for low collisionality plasmas. When the SEE coefficient of the electrons bordering the depleted loss cone in energy space exceeds unity, the sheath potential is unstable to a negative perturbation. This result explains three different instability phenomena observed in Hall thruster simulations including a newly found state with spontaneous ~20MHz oscillations. When instabilities occur, the SEE propagating between the walls becomes the dominant contribution to the particle flux, energy loss and axial transport.

Research Organization:
Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
Sponsoring Organization:
USDOE Office of Science (SC)
DOE Contract Number:
De-AC02-09CH11466
OSTI ID:
1062660
Report Number(s):
PPPL-4762
Country of Publication:
United States
Language:
English