Premium
On the thermal noise “temperature” in an anisotropic plasma
Author(s) -
MeyerVernet Nicole
Publication year - 1994
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/94gl00197
Subject(s) - plasma , physics , dipole , polarization (electrochemistry) , perpendicular , directivity , electron temperature , johnson–nyquist noise , anisotropy , computational physics , thermal , magnetic field , electron , noise (video) , optics , condensed matter physics , antenna (radio) , geometry , chemistry , telecommunications , mathematics , quantum mechanics , artificial intelligence , detector , meteorology , computer science , image (mathematics)
Electrostatic waves are often detected with wire dipoles longer than the wave‐lengths. The electrostatic directivity pattern of such antennas has lobes roughly perpendicular to those of short dipoles. As a consequence, in a plasma where the electron temperatures are different along ( T ║ ) and across ( T ⟂ ) the magnetic field, the thermal noise “temperature” is T ⟂ if the antenna is parallel to B and ( T ║ + T ⟂ )/2 if it is perpendicular. Practical applications for space plasma and wave polarization measurements are given.