Cross-Field Motion of Plasma Blobs in an Open Magnetic Field Line Configuration
- Centre de Recherches en Physique des Plasmas, Ecole Polytechnique Federale de Lausanne (EPFL), Association EURATOM-Confederation Suisse, CH-1015 Lausanne (Switzerland)
The radial propagation of blobs generated from plasma instabilities is investigated in an open magnetic field line configuration. Blob cross-field velocities and sizes are obtained from internal probe measurements using pattern recognition. By varying the ion mass, the normalized vertical blob scale a-tilde is scanned from a-tilde<1 to a-tilde>1. An analytical expression for the blob velocity including cross-field ion polarization currents, parallel currents to the sheath, and ion-neutral collisions is derived and shows good quantitative agreement with the experimental data. In agreement with previous theoretical studies, this scaling shows that, for a-tilde<1, the blob velocity is limited by cross-field ion polarization currents, while for a-tilde>1 it is limited by parallel currents to the sheath.
- OSTI ID:
- 21370638
- Journal Information:
- Physical Review Letters, Vol. 103, Issue 6; Other Information: DOI: 10.1103/PhysRevLett.103.065001; (c) 2009 The American Physical Society; ISSN 0031-9007
- Country of Publication:
- United States
- Language:
- English
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