טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentMoshe Donskoy
SubjectNumerical Simulations of Plasma Formation in High-Power
Microwave Compressor
DepartmentDepartment of Physics
Supervisors Full Professor Krasik Yakov
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Full Thesis textFull thesis text - English Version


Abstract

A numerical simulation work, studying the process of nanosecond timescale plasma formation in a high-power microwave (HPM) compressor, was carried out. The plasma is formed inside interference switch in the presence of intense electromagnetic field which is stored in the HPM compressor. The compressor operation is based on microwave energy storage in a resonant cavity during its first stage of operation, and a fast release of the electromagnetic energy from this cavity during the second stage.

Space and time evolution of plasma formation in the HPM compressor is critical for a successful energy release. Indeed, the requirement for a formation of a so called “interference switch”, which is what causes the compressor to release its stored energy, is in the timescale of several nanoseconds. The latter relates to transient time of electromagnetic wave propagation in the resonant cavity.

Therefore, switching between the stages of microwave energy storage and release is a crucial process determining the optimal performance and efficiency of an HPM compressor operation. Especially, the characteristics of the output microwave pulse (duration, power, duration and stability) correlate strongly with the parameters of the plasma generated in interference switch.

Fast switching of stored electromagnetic energy can be achieved using the plasma with plasma density sufficient for effective reflection of microwaves. Since, the formation of such plasma can be achieved within the nanosecond time scale, a plasma based interference switch makes a very promising method of achieving the desired switching time and efficiency. Though there has been a significant progress in experimental studies of compressors, at the present time, there is no clear understanding of the processes which govern plasma formation and its expansion in the presence of a high-frequency electromagnetic field in pressurized gases.

A numerical research based on results obtained in experiments with microwave compressor having plasma interference switch, was carried out by a team of researchers from the Technion, resulting in three published papers where these experimental and numerical results were presented and discussed.

In this thesis, I describe and discuss my part of this research which was focused on the numerical simulations carried out using MAGIC code and CST software, of the plasma formation in interference switch for different gas pressure and power of the microwaves.