000119321 001__ 119321
000119321 005__ 20190102122015.0
000119321 0247_ $$2doi$$a10.1063/1.859825
000119321 022__ $$a0899-8221
000119321 02470 $$2ISI$$aA1991FN76500001
000119321 037__ $$aARTICLE
000119321 245__ $$aVelocity Ratio Measurement Using the Frequency of the Gyro Backward-Wave
000119321 260__ $$c1991
000119321 269__ $$a1991
000119321 336__ $$aJournal Articles
000119321 520__ $$aThe operating diagram of a low quality factor, 8 GHz TE-degrees-01 gyrotron exhibits oscillations between 6.8 and 7.3 GHz. These oscillations are identified as the backward wave component of the TE-degrees-21 traveling mode. As the resonance condition of this mode depends on the average parallel velocity <upsilon-parallel-to> of the beam electrons (omega-BW approximately-or-equal-to OMEGA-c/gamma-k parallel-to <upsilon-parallel-to>), the measurement of omega-BW for given OMEGA-c and gamma is used as a diagnostic for the beam electrons velocity ratio alpha = <upsilon-perpendicular-to>/<upsilon-parallel-to>. The values of alpha, deduced from omega-BW through the linear dispersion relation for the electron cyclotron instability in an infinite waveguide, are unrealistic. A nonlinear simulation code gives alpha values that are in very good agreement with the ones predicted by a particle trajectory code (+ 10% to + 20%). It is found numerically that the particles' velocity dispersion in upsilon-perpendicular-to and upsilon-parallel-to increases omega-BW. This effect explains part of the discrepancy between the values of alpha inferred from omega-BW without velocity dispersion and the expected values.
000119321 700__ $$aMuggli, P.
000119321 700__ $$0241171$$aTran, M. Q.$$g106568
000119321 700__ $$0240103$$aTran, T. M.$$g106569
000119321 773__ $$j3$$k6$$q1315-1318$$tPhysics of Fluids B-Plasma Physics
000119321 909C0 $$pCRPP
000119321 909C0 $$0252028$$pSPC
000119321 909CO $$ooai:infoscience.tind.io:119321$$pSB$$particle
000119321 937__ $$aCRPP-ARTICLE-1991-012
000119321 973__ $$aEPFL$$rREVIEWED$$sPUBLISHED
000119321 980__ $$aARTICLE