Helicon waves in uniform plasmas. IV. Bessel beams, Gendrin beams, and helicons

被引:19
作者
Urrutia, J. M. [1 ]
Stenzel, R. L. [1 ]
机构
[1] Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA
基金
美国国家科学基金会;
关键词
FLUX ROPES; ANTENNA; EXCITATION; WHISTLERS; VORTICES; PROPAGATION; DIFFRACTION;
D O I
10.1063/1.4949348
中图分类号
O35 [流体力学]; O53 [等离子体物理学];
学科分类号
070204 ; 080103 ; 080704 ;
摘要
Electromagnetic waves in the low frequency whistler mode regime are investigated experimentally and by digital data superposition. The radiation from a novel circular antenna array is shown to produce highly collimated helicon beams in a uniform unbounded plasma. The differences to Bessel beams in free space are remarked upon. Low divergence beams arise from the parallel group velocity of whistlers with phase velocity either along the guide field or at the Gendrin angle. Waves with angular momentum are produced by phasing the array in the circular direction. The differences in the field topologies for positive and negative modes numbers are shown. It is also shown that in uniform plasmas, the radial amplitude profile of the waves depends on the antenna field topology. Thus, there are no helicon "eigenmodes" with radial Bessel function profiles in uniform plasmas. It is pointed out that phase measurements in helicon devices indicate radial wave propagation which is inconsistent with helicon eigenmode theory based on paraxial wave propagation. Trivelpiece-Gould modes also exist in uniform unbounded plasmas. Published by AIP Publishing.
引用
收藏
页数:13
相关论文
共 40 条
[21]   Helicon mode formation and radio frequency power deposition in a helicon-produced plasma [J].
Niemi, K. ;
Kraemer, M. .
PHYSICS OF PLASMAS, 2008, 15 (07)
[22]  
Nyquist H., 1928, Transactions of the American Institute of Electrical Engineers, V47, P617, DOI DOI 10.1109/T-AIEE.1928.5055024
[23]   PULSED CURRENTS CARRIED BY WHISTLERS .5. DETAILED NEW RESULTS OF MAGNETIC ANTENNA EXCITATION [J].
ROUSCULP, CL ;
STENZEL, RL ;
URRUTIA, JM .
PHYSICS OF PLASMAS, 1995, 2 (11) :4083-4093
[24]   A segmented multi-loop antenna for selective excitation of azimuthal mode number in a helicon plasma source [J].
Shinohara, S. ;
Tanikawa, T. ;
Motomura, T. .
REVIEW OF SCIENTIFIC INSTRUMENTS, 2014, 85 (09)
[25]   Development of very large helicon plasma source [J].
Shinohara, S ;
Tanikawa, T .
REVIEW OF SCIENTIFIC INSTRUMENTS, 2004, 75 (06) :1941-1946
[26]   Magnetospherically reflected, specularly reflected, and backscattered whistler mode radio-sounder echoes observed on the IMAGE satellite: 1. Observations and interpretation [J].
Sonwalkar, V. S. ;
Carpenter, D. L. ;
Reddy, A. ;
Proddaturi, R. ;
Hazra, S. ;
Mayank, K. ;
Reinisch, B. W. .
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, 2011, 116
[27]   Helicon modes in uniform plasmas. III. Angular momentum [J].
Stenzel, R. L. ;
Urrutia, J. M. .
PHYSICS OF PLASMAS, 2015, 22 (09)
[28]   Helicon waves in uniform plasmas. II. High m numbers [J].
Stenzel, R. L. ;
Urrutia, J. M. .
PHYSICS OF PLASMAS, 2015, 22 (09)
[29]   Magnetic antenna excitation of whistler modes. IV. Receiving antennas and reciprocity [J].
Stenzel, R. L. ;
Urrutia, J. M. .
PHYSICS OF PLASMAS, 2015, 22 (07)
[30]   Helicons in Unbounded Plasmas [J].
Stenzel, R. L. ;
Urrutia, J. M. .
PHYSICAL REVIEW LETTERS, 2015, 114 (20)