Accession Number:

ADA237427

Title:

Evolution of a Finite Pulse of Radiation in a High-Power Free-Electron Laser

Descriptive Note:

Memorandum rept.,

Corporate Author:

NAVAL RESEARCH LAB WASHINGTON DC

Personal Author(s):

• Ting, A.
• Hafizi, B.
• Sprangle, P.
• Tang, C. M.

Report Date:

1991-06-20

Pagination or Media Count:

42.0

Abstract:

The development of an optical pulse of finite axial extent is studied by means of an axisymmetric, time-dependent, particle simulation code for different rates of tapering of the wiggler field. The results illustrate a number of the physical phenomena underlying the free-electron laser mechanism. These include suppression of the sideband instability the role of gain focusing versus that of refractive guiding efficiency enhancement and pulse slippage. It is found that a significant reduction in the sideband modulation of the optical field can be achieved with a faster tapering of the wiggler parameters. Increasing the tapering rate also reduces refractive guiding, causing the optical wavefronts to become more convex, thus spreading the optical field into a large cross-section. The corresponding enhancement of the peak output power is associated with an increased lateral extent of the optical field rather than an increase in the field amplitude. Author

Descriptors:

• *HIGH POWER
• SIMULATION
• OPTICAL PROPERTIES
• RADIATION
• STABILITY
• OPTIMIZATION
• PHYSICAL PROPERTIES
• EFFICIENCY
• CODING
• PEAK POWER
• FREE ELECTRON LASERS
• PARTICLES
• PULSES
• LIGHT PULSES
• CROSS SECTIONS
• GAIN
• FOCUSING
• SIDEBANDS
• MODULATION
• AMPLITUDE
• WAVEFRONTS
• OUTPUT

Subject Categories:

• Lasers and Masers
• Particle Accelerators

Distribution Statement:

APPROVED FOR PUBLIC RELEASE