First Direct Observation of Runaway-Electron-Driven Whistler Waves in Tokamaks

被引：92

作者：

Spong, D. A. ^{[1
]}

Heidbrink, W. W. ^{[2
]}

Paz-Soldan, C. ^{[3
]}

Du, X. D. ^{[2
]}

Thome, K. E. ^{[4
]}

Van Zeeland, M. A. ^{[3
]}

Collins, C. ^{[3
]}

Lvovskiy, A. ^{[4
]}

Moyer, R. A. ^{[5
]}

Austin, M. E. ^{[6
]}

Brennan, D. P. ^{[7
]}

Liu, C. ^{[7
]}

Jaeger, E. F. ^{[8
]}

Lau, C. ^{[1
]}

机构：

[1] Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA

[2] Univ Calif Irvine, Irvine, CA 92697 USA

[3] Gen Atom, San Diego, CA 92186 USA

[4] Oak Ridge Associated Univ, POB 117, Oak Ridge, TN 37831 USA

[5] Univ Calif San Diego, La Jolla, CA 92093 USA

[6] Univ Texas Austin, Austin, TX 78705 USA

[7] Princeton Plasma Phys Lab, POB 451, Princeton, NJ 08543 USA

[8] XCEL Engn, Oak Ridge, TN 37830 USA

来源：

PHYSICAL REVIEW LETTERS | 2018年 / 120卷 / 15期

关键词：

SPACE;

D O I：

10.1103/PhysRevLett.120.155002

中图分类号：

O4 [物理学];

学科分类号：

0702 ;

摘要：

DIII-D experiments at low density (n(e) similar to 10(19) m(-3)) have directly measured whistler waves in the 100-200 MHz range excited by multi-MeV runaway electrons. Whistler activity is correlated with runaway intensity (hard x-ray emission level), occurs in novel discrete frequency bands, and exhibits nonlinear limit-cycle-like behavior. The measured frequencies scale with the magnetic field strength and electron density as expected from the whistler dispersion relation. The modes are stabilized with increasing magnetic field, which is consistent with wave-particle resonance mechanisms. The mode amplitudes show intermittent time variations correlated with changes in the electron cyclotron emission that follow predator-prey cycles. These can be interpreted as wave-induced pitch angle scattering of moderate energy runaways. The tokamak runaway-whistler mechanisms have parallels to whistler phenomena in ionospheric plasmas. The observations also open new directions for the modeling and active control of runaway electrons in tokamaks.

引用

页数：5

共 23 条

[1] Stability analysis of runaway-driven waves in a tokamak [J].