Plasma control by modification of helicon wave propagation in low magnetic fields
- Space Plasma, Power and Propulsion Group, Research School of Physics and Engineering, Australian National University, Canberra, Australian Capital Territory 0200 (Australia)
By making use of nonuniform magnetic fields, it is shown experimentally that control of helicon wave propagation can be achieved in a low pressure (0.08 Pa) expanding plasma. The m=1 helicon waves are formed during a direct capacitive to wave mode transition that occurs in a low diverging magnetic field (B{sub 0}<3 mT). In this initial configuration, waves are prevented from reaching the downstream region, but slight modifications to the magnetic field allows the axial distance over which waves can propagate to be controlled. By changing the effective propagation distance in this way, significant modification of the density and plasma potential profiles can be achieved, showing that the rf power deposition can be spatially controlled as well. Critical to the modification of the wave propagation behavior is the magnetic field strength (and geometry) near the exit of the plasma source region, which gives electron cyclotron frequencies close to the wave frequency of 13.56 MHz.
- OSTI ID:
- 21389149
- Journal Information:
- Physics of Plasmas, Vol. 17, Issue 7; Other Information: DOI: 10.1063/1.3460351; (c) 2010 American Institute of Physics; ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
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