Developmental Aspects of Microwave-Plasma Interaction Experiments: Phase-1

• Published in: IEEE transactions on plasma science 2016-10, Vol.44 (10), p.2226-2231
• Main Authors: Anitha, V. P., Rathod, Priyavandana J., Singh, Raj, Giri, D. V.
• Format: Article
• Language: English
• Subjects: Circulators; Couplings; Discharges (electric); Electric fields; Electrons; High-power microwave (HPM); Modulation; Physics; plasma; Plasma physics; Plasmas; Probes; wave–plasma interaction
• ISSN: 0093-3813; 1939-9375
• DOI: 10.1109/TPS.2016.2552643

An experimental system, SYstem for Microwave PLasma Experiments (SYMPLE), is being developed in order to investigate the physics of linear and nonlinear interaction of a high-power microwave (HPM) with an overdense plasma (plasma frequency f p > microwave frequency f μ ). The physics of interaction has implications in inertial fusion. The developmental task is taken up in two phases: Phase-1 using moderate microwave power (~3 MW), satisfying the condition 1/ 2εo E 2 μ /ne kT e ~ 1 and Phase-2 involving HPM sources of much higher power. Here, Eμ is the microwave electric field, ne the plasma electron density, Te the electron temperature, m the electron mass, ε o is the free space permittivity, and k is the Boltzmann constant. The Phase-1 system consists of a pulsed (5 μs), S-band magnetron (3 MW, 3 GHz) coupled to a pulsed (100 μs) washer-gun plasma (ne~ 1 × 10 18 /m 3 ). The tasks associated with interfacing of the magnetron and plasma have involved the indigenous design and development of different subsystems, each satisfying the specific technical requisites of the Phase-1 system. These subsystems include a washer-gun plasma (n e ~ 1 × 10 18 /m 3 ) driven by a pulse forming network, a line-type modulator (52-KV 120-A, 5-μs pulsewidth, ~450-ns rise time) that drives the S-band magnetron, an HPM-plasma coupling system, and an HPM TE 10 - TM 01 mode converter. The developmental aspects of the subsystems form the subject of this paper.