DocumentCode :
1934451
Title :
Diagnostics of magnetic antenna fields for low frequency whistlers in r-t and /spl omega/-k space
Author :
Rousculp, C.L. ; Urrutia, J.M. ; Stenzel, R.L.
Author_Institution :
Dept. of Phys., California Univ., Los Angeles, CA, USA
fYear :
1993
fDate :
7-9 June 1993
Firstpage :
140
Abstract :
Summary form only given. In a large uniform laboratory plasma the magnetic field B/sub (r,t)/ of a shielded magnetic loop antenna (5 cm diam.) has been measured in both near and far zones. The antenna is driven with a single short current pulse which excites a whistler wave packet. With a movable magnetic probe and repeated pulses the vector field B/sub x/, B/sub z/ vs. x, y, z is mapped at 10,000 spatial positions with high time resolution. In the space-time domain the evolution of a dispersive wave packet from the antenna near-zone fields is observed. The wave packet consists of nested cones propagating with wave normals highly oblique to B/sub o/ but energy flow at a small angle to B/sub o/. In order to analyze the wave packet in terms of eigenmodes, the field B/sub (r,t)/ has been Fourier-transformed in time and 3-D space, B/sub (/spl omega/,k)/. At a selected frequency, the finite-size antenna launches a spectrum of k-vectors which, for an antenna dipole moment along B/sub o/, is highly axisymmetric. In the k/sub /spl perp - k/sub 1/ plane the wave energy is spread out along the refractive index curve of whistlers with the largest wave energy oblique to B/sub o/.
Keywords :
plasma diagnostics; 5 cm; antenna dipole moment; antenna near-zone fields; dispersive wave packet; energy flow; finite-size antenna; large uniform laboratory plasma; low frequency whistlers; magnetic antenna fields; movable magnetic probe; nested cones; plasma diagnostics; refractive index curve; repeated pulses; shielded magnetic loop antenna; single short current pulse; space-time domain; Antenna measurements; Dipole antennas; Frequency; Laboratories; Magnetic field measurement; Magnetic moments; Magnetic shielding; Plasma diagnostics; Plasma measurements; Plasma waves;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Plasma Science, 1993. IEEE Conference Record - Abstracts., 1993 IEEE International Conference on
Conference_Location :
Vancouver, BC, Canada
ISSN :
0730-9244
Print_ISBN :
0-7803-1360-7
Type :
conf
DOI :
10.1109/PLASMA.1993.593407
Filename :
593407
Link To Document :
بازگشت