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Transport Coefficients in the Jet Boundary
Author(s) -
Lowry C. G.,
Harbour P. J.,
Tagle J. A.
Publication year - 1988
Publication title -
contributions to plasma physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.531
H-Index - 47
eISSN - 1521-3986
pISSN - 0863-1042
DOI - 10.1002/ctpp.2150280413
Subject(s) - jet (fluid) , langmuir probe , electron , electron temperature , electron density , plasma , ohmic contact , computational physics , atomic physics , physics , flux (metallurgy) , effective radiated power , materials science , mechanics , power (physics) , plasma diagnostics , layer (electronics) , nuclear physics , thermodynamics , metallurgy , composite material
Langmuir probes mounted in an antenna protection tiles have facilitated the comprehensive measurement of electron temperatures and densities in the JET scrape‐off layer (sol) 2 . The probes are close to the outside midplane and at radial positions of 15 and 28 mm behind the last closed flux surface. The data are from ohmic discharges with plasma currents between 1 and 5 MA and average electron densities between 8 × 10 18 and 5 × 10 19 m −3 . Here we use these measurements in a simple diffusive model for the electrons to obtain empirical scalings of the transport coefficients with local parameters. The scalings are shown to be inconsistent with exponentially decaying profiles of electron temperature and density, such as are measured in the JET sol. In the apparent absence of a suitable model we are forced to scale directly the characteristic decay lengths in similar fashion. Finaally we use these dependences to campare models of global particle and power balance with the data.