Whistler Wave Excitation and Effects of Self-Focusing on Ion Beam Propagation through a Background Plasma along a Solenoidal Magnetic Field

Mikhail, Dorf A. ; Kaganovich, Igor D. ; Startsev, Edward A. ; Davidson, Ronald C.

关键词: CYCLOTRON FREQUENCY;    ELECTROMAGNETIC FIELDS;    ELECTRONS;    EXCITATION;    ION BEAMS;    LANGMUIR FREQUENCY;    LORENTZ FORCE;    MAGNETIC FIELDS;    PLASMA;    TRANSPORT;    VELOCITY;    WHISTLERS Whistler Waves;    Beam Plasma Interactions;   

DOI  :  10.2172/973083
RP-ID  :  PPPL-4487
PID  :  OSTI ID: 973083
Others  :  TRN: US1002740

学科分类：原子、分子光学和等离子物理

美国|英语

来源: SciTech Connect

【 摘 要 】

This paper extends studies of ion beam transport through a background plasma along a solenoidal magnetic field [I. Kaganovich et al., Phys. Plasmas 15, 103108 (2008)] to the important regime of moderate magnetic field strength satisfying ??ce > 2??b??pe . Here, ??ce and ?? pe are the electron cyclotron frequency and electron plasma frequency, respectively, and ??b = vb/ c is the directed ion beam velocity normalized to the speed of light. The electromagnetic field perturbations excited by the ion beam pulse in this regime are calculated analytically, and verified by comparison with the numerical simulations. The degrees of beam charge neutralization and current neutralization are estimated, and the transverse component of the Lorentz force associated with the excited electromagnetic field is calculated. It is found that the plasma response to the ion beam pulse is significantly different depending on whether the value of the solenoidal magnetic field is below or above the threshold value specified by ?? cr ce = 2??b??pe, and corresponding to the resonant excitation of large-amplitude whistler waves. The use of intense whistler wave excitations for diagnostic purposes is also discussed.