Conversion of a whistler wave into a controllable helical wiggler magnetic field

Conference · Tue Dec 31 04:00:00 EST 1996

OSTI ID:438840

Kalluri, D K ^[1]

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1. Univ. of Massachusetts, Lowell, MA (United States). Dept. of Electrical Engineering

Coherent radiation generated in a Free Electron Laser (FEL) is due to the interaction of an electron beam with a wiggler magnetic field which is a spatially varying static (zero frequency) magnetic field. Linear or helical wigglers can be constructed from electromagnets or permanent magnets. The wavelength {lambda} of the output radiation depends on ({lambda}{sub w}) the wiggler wavelength, (K{sub w}) the wiggler strength parameter and (v{sub 0}) the velocity of the electron beam. The tunability of FEL comes from the variability of the kinetic energy of the electrons. When once a FEL is constructed {lambda}{sub W} is fixed. This paper deals with the principle of establishing a helical wiggler magnetic field with controllable {lambda}{sub w}. A whistler wave which propagates in a magnetoplasma when the source frequency {omega}{sub 0} is less than the electron gyrofrequency {omega}{sub b}, gives rise to a wiggler magnetic field in the plasma when the static magnetic field is switched off. The strength and the period of the wiggler field depends on the parameters of the magnetoplasma medium. When the parameters are such that {omega}{sub 0} is much less than {omega}{sub b} and {omega}{sub p}, the total energy of the source wave is converted into the magnetic energy of the wiggler field.

• OSTI ID: 438840
• Report Number(s): CONF-960634--
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
ENERGY CONVERSION
FREE ELECTRON LASERS
MAGNETIC FIELDS
PLASMA
RADIOWAVE RADIATION
TUNING
WAVELENGTHS
WIGGLER MAGNETS