Experimental Evidence of a Double Layer in a Large Volume Helicon Reactor
- Space Plasma and Plasma Processing Group, Plasma Research Laboratory, Research School of Physical Sciences and Engineering, Australian National University, Acton 0200, Canberra (Australia)
The self-consistently generated current-free electric double layer (DL) is shown to scale up with the source tube diameter and appears not to be affected by rf driving frequency and changes in reactor geometry. This Letter presents the first simultaneous measurements of local plasma potential and beam energy as a function of axial position. The DL is shown to be no more than 5 mm thick (20 D lengths) and positioned just downstream of the maximum in the magnetic field gradient. Furthermore, its position relative to the magnetic field is observed to be invariant as the magnetic field is translated axially. Measurements of the potential drop across the DL are presented for pressures down to 0.09 mTorr and the DL strength ({phi}{sub DL}/T{sub e}) is determined to be between 5 and 7.
- OSTI ID:
- 20699566
- Journal Information:
- Physical Review Letters, Vol. 95, Issue 20; Other Information: DOI: 10.1103/PhysRevLett.95.205002; (c) 2005 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0031-9007
- Country of Publication:
- United States
- Language:
- English
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