Simulations of the performance of the Fusion-FEM, for an increased e-beam emittance

Conference · Sun Dec 31 04:00:00 EST 1995

OSTI ID:238808

Tulupov, A V ^[1]; Urbanus, W H ^[2]; Caplan, M ^[3]

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1. Institute for Nuclear Fusion, Moscow (Russian Federation)
2. FOM-Institute for Plasma Physics, Nieuwegein (Netherlands)
3. Lawrence Livermore National Lab., CA (United States)

The original design of the Fusion-FEM, which is under construction at the FOM-Institute for Plasma Physics, was based on an electron beam emittance of 50 {pi} mm mrad. Recent measurements of the emittance of the beam emitted by the electron gun showed that the actual emittance is 80 {pi} mm mrad. This results in a 2.5 times lower beam current density inside the undulator. As a result it changes the linear gain, the start-up time, the saturation level and the frequency spectrum. The main goal of the FEM project is to demonstrate a stable microwave output power of at least 1 MW. The decrease of the electron beam current density has to be compensated by variations of the other FEM parameters, such as the reflection (feedback) coefficient of the microwave cavity and the length of the drift gap between the two sections of the step-tapered undulator. All basic dependencies of the linear and nonlinear gain, and of the output power on the main FEM parameters have been simulated numerically with the CRMFEL code. Regimes of stable operation of the FEM with the increased emittance have been found. These regimes could be found because of the original flexibility of the FEM design.

• Research Organization: Brookhaven National Lab., Upton, NY (United States)
• OSTI ID: 238808
• Report Number(s): BNL--61982-Absts.; CONF-9508156--Absts.; ON: DE96002729
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
43 PARTICLE ACCELERATORS
70 PLASMA PHYSICS AND FUSION TECHNOLOGY
BEAM EMITTANCE
DESIGN
ELECTRON GUNS
FREE ELECTRON LASERS
MASERS
PERFORMANCE
SIMULATION