Generation of High-Power Sub-THz Waves in Magnetized Turbulent Electron Beam Plasmas

• Published in: Journal of infrared, millimeter and terahertz waves Vol. 35; no. 1; pp. 81 - 90
• Main Authors: Thumm, M. K. A., Arzhannikov, A. V., Astrelin, V. T., Burdakov, A. V., Ivanov, I. A., Kalinin, P. V., Kandaurov, I. V., Kurkuchekov, V. V., Kuznetsov, S. A., Makarov, M. A., Mekler, K. I., Polosatkin, S. V., Popov, S. A., Postupaev, V. V., Rovenskikh, A. F., Sinitsky, S. L., Sklyarov, V. F., Stepanov, V. D., Trunev, Yu. A., Timofeev, I. V., Vyacheslavov, L. N.
• Format: Journal Article
• Language: English
• Published: Boston Springer US 2014
• Subjects: Classical Electrodynamics; Current density; Density; Electrical Engineering; Electronics and Microelectronics; Engineering; Fluid dynamics; Fluid flow; Instrumentation; Plasma density; Plasmas; Turbulence; Turbulent flow; Relativistic electron beam; Langmuir turbulence; High-power sub-THz wave generation; Non-linear three-wave interaction
• ISSN: 1866-6892; 1866-6906
• DOI: 10.1007/s10762-013-9969-3

Sub-THz radiation can be generated by conversion of plasma waves into electromagnetic (EM) radiation in a plasma with strong Langmuir (LT) turbulence produced via a two-stream instability of a high current relativistic electron beam (REB). Nonlinear plasmon-plasmon merging results in the generation of photons nearby the 2
nd
harmonic of the plasma frequency 2
ω
p
(“2
ω
p
-process”). For plasma densities of 10
14
 − 10
15
 cm
−3
, these frequencies are in the range of sub-THz waves at 370–570 GHz. The specific power density of sub-THz-wave emission from plasmas in the multi-mirror magnetic trap GOL-3 (at BINP) during injection of a 10-μs-REB with a current density of about 1 kA/cm
2
at plasma densities
n
e
 ≈ 5∙10
14
 cm
−3
, electron temperatures
T
e
 ≈ 1.5 keV and magnetic induction
B
 ≈ 4 T was measured to be approx. 1 kW/cm
3
in the frequency band around 300 GHz. In the case of a weakly relativistic 100-μs-electron beam (90 keV) with 250 A/cm
2
the corresponding results are 700 W/cm
3
around 90 GHz with an efficiency of 1–2 % at
n
e
 ≈ 3∙10
13
 cm
−3
(total power ≈ 30 kW). Theoretical investigations show that at a density of
n
e
 ≈ 3∙10
15
 cm
−3
and a turbulence level of 5 % the generated sub-THz power can reach ≈ 1 MW/cm
3
.