Nonlocal theory of a whistler pumped free electron laser

Journal Article · Fri Apr 01 04:00:00 EST 1994 · Physics of Plasmas; (United States)

DOI:https://doi.org/10.1063/1.870782· OSTI ID:6685863

Pant, K K; Tripathi, V K ^[1]

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1. Department of Physics, Indian Institute of Technology Hauz Khas, New Delhi 110 016 (India)

A cylindrical waveguide loaded with a magnetized plasma supports a short wavelength whistler mode. In the presence of a relativistic electron beam the whistler mode couples to a negative energy beam mode and a high-frequency electromagnetic mode giving coherent radiation. A nonlocal theory of the process reveals that larger beam cross section is preferable for better coupling. The phase matching conditions give the frequency of operation as [omega][sub 1]=([ital ck][sub 0[ital z]]/[eta][sub 0])[([eta][sub 0][minus][eta])/([eta][minus][eta][sub 1])] where [omega][sub 1] is the frequency of the free electron laser radiation, [ital k][sub 0[ital z]] is the wave number of the pump wave, [ital c] is the velocity of light in free space, and [eta][sub [ital j]]=[ital ck][sub [ital j]]/[omega][sub [ital j]], [eta][sub [ital j]]=[eta][sub 0], [eta][sub 1], [eta] correspond to the pump, radiation signal, and the beam mode, respectively. The frequency of radiation is maximum when it propagates in the transverse magnetic TM[sub 01] mode. As the frequency of the whistler approaches electron cyclotron frequency, the frequency of radiation is enhanced while the growth time also increases. The growth time scales as [gamma][sup 9/2][sub 0][ital k][sup 3/2][sub 0[ital z]][omega][sup 1/2] [[omega][sup 2][sub [ital c]][minus][gamma][sup 2][sub 0]([omega][sub 0][minus][ital k][sub 0[ital z]v][sub [ital b]])[sup 2]][sup 1/2] /([omega][sup 2][sub [ital pb]][omega][sup 1/2][sub 1)].

• OSTI ID: 6685863
• Journal Information: Physics of Plasmas; (United States), Journal Name: Physics of Plasmas; (United States) Vol. 1:4; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700340* -- Plasma Waves
Oscillations
& Instabilities-- (1992-)
700350 -- Plasma Production
Heating
Current Drive
& Interactions-- (1992-)
BEAMS
COHERENT RADIATION
CYCLOTRON FREQUENCY
CYCLOTRON RESONANCE
ELECTRICAL EQUIPMENT
ELECTROMAGNETIC RADIATION
ELECTROMAGNETS
ELECTRON BEAMS
EQUIPMENT
FREE ELECTRON LASERS
INSTABILITY GROWTH RATES
LASERS
LEPTON BEAMS
MAGNETS
NOISE
OPERATION
PARTICLE BEAMS
RADIATIONS
RADIO NOISE
RADIOWAVE RADIATION
RESONANCE
WAVEGUIDES
WHISTLERS
WIGGLER MAGNETS