Linearized magnetohydrodynamic theory of Langmuir probes with resistivity, friction, and polarization
| ISSN: |
1089-7674
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| Source: |
AIP Digital Archive
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| Topics: |
Physics
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| Notes: |
Standard Langmuir probe analysis interprets the entire voltage drop to occur in the sheath and neglects any voltage drop due to bulk resistivity. In a magnetized plasma this implies a strong mechanism to damp the E×B drift around the probe's flux tube. Application of linearized magnetohydrodynamics to the bulk plasma allows the consideration of a variety of geometries and damping mechanisms on an equal footing and the treatment of plasma turbulence without the inappropriate recourse to anomalous transport coefficients. An analytic expression for the apparent temperature determined by long flush mounted Langmuir probes can be found if the boundary conditions are also linearized. The friction on neutrals is always stronger than viscosity and is able to account for all the I–V characteristics measured in the ASDEX Upgrade [M. Kaufmann et al., Plasma Physics and Controlled Fusion 35, 205 (1993)] divertor. At all but the lowest densities, the polarization term associated with E×B drifts is stronger still. © 2001 American Institute of Physics.
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| Type of Medium: |
Electronic Resource
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| URL: |