51st Annual Meeting of the APS Division of Plasma Physics
Volume 54, Number 15
Monday–Friday, November 2–6, 2009;
Atlanta, Georgia
Session CI2: Accelerators, Beam Dynamics and Radiation
2:00 PM–5:00 PM,
Monday, November 2, 2009
Room: Centennial I
Chair: Joe Kwan, Lawrence Berkeley National Laboratory
Abstract ID: BAPS.2009.DPP.CI2.5
Abstract: CI2.00005 : Advances in Modeling of Beam-Wave Interaction in Multi-Megawatt Gyrotrons*
4:00 PM–4:30 PM
Preview Abstract
Abstract
Author:
Alexander Vlasov
(Naval Research Laboratory)
High-power gyrotrons, capable to produce several megawatts of CW
radiation
in millimeter wave range, are used in many magnetic fusion
facilities, and
planned to be used in ITER. The gyrotrons employ an interaction
between a
gyrating electron beam and very high order modes of open
cylindrical or
co-axial cavities to keep Ohmic losses on cavity walls on
acceptable level.
Since the gyrotron cavity supports a large number of eigenmodes with
different azimuthal and radial indexes many of which are capable of
interaction with electron beam at different frequencies. The code
MAGY [1,2]
has been developed to address the mode competition issue in
gyro-devices.
MAGY model is based on multi time-scale approach and uses
electromagnetic
fields expansion into series of eigenfunctions of local transverse
cross-section. This approach leads to computationally efficient
solution of
the Maxwell's Equations. MAGY has been used for design and
modeling of
gyro-devices in CPI, MIT, UMD, NRL for last decade and demonstrated
excellent agreement with experimental data. Modeling of
Multi-Megawatt
gyrotrons operating at high frequencies (170 GHz and above)
presents a new
challenge due to the unprecedented level of spectral mode density
and higher
level of beam current. A co-axial cavity gyrotron has been
introduced to
reduce this spectral density. To address these computational physics
challenges a new MAGY model for mode interaction in gyrotrons
with co-axial
cavities has been implemented. MAGY has been used to model the
FZK (Germany)
170 GHz co-axial gyrotron [3,4]. The results of this modeling
will be
presented. Further advances in the theoretical models for
comparison with
the existing experimental data will be discussed.
\\[4pt]
[1] S.C. Cai, et al, \textit{Int. J. Elect.}, 72, p. 759,
1992.\\[0pt]
[2] M. Botton, et al, \textit{IEEE Trans on P S, }26, p. 882,
1998.\\[0pt]
[3] B. Piosczyk, et al, \textit{IEEE Trans. on P S}., 32, 413,
2004.\\[0pt]
[4] A.N. Vlasov, et al, \textit{IEEE Trans. on P S}., 36, p. 606,
2008.
*This work was supported by the U.S. Office of Naval Research.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2009.DPP.CI2.5