Observations of strong microwave absorption in collisional plasmas with gradual density gradients

Autor:	K. R. Stalder, R. J. Vidmar, D. J. Eckstrom
Rok vydání:	1992
Předmět:	Electron density Wavelength Physics::Plasma Physics Scattering Chemistry General Physics and Astronomy Plasma diagnostics Astrophysics::Cosmology and Extragalactic Astrophysics Plasma Photoionization Atomic physics Absorption (electromagnetic radiation) Microwave
Zdroj:	Journal of Applied Physics. 72:5089-5094
ISSN:	1089-7550 0021-8979
DOI:	10.1063/1.352038
Popis:	Strong microwave absorption was observed when a 10 GHz source illuminated an underdense collisional plasma that had a density gradient scale length several wavelengths long. Significant reductions in angular scattering and cross‐polarized components were also observed. These experiments confirm that absorption was the dominant process. The plasma was created by the photoionization of tetrakisdimethylaminoethylene molecules seeded into atmospheric pressure helium. Sparkboard arrays provided the intense vacuum ultraviolet ionizing radiation. Plasma density profiles were measured using transverse scans of 9.7 GHz probe microwaves and were found to approximate an Epstein profile. The absorption at 10 GHz by this plasma was as large as 28 dB in direct backscattering and 15–20 dB when orthogonally polarized microwaves were launched and detected. The peak absorption scales with sparkboard energy in a way that suggests that electron‐ion recombination is the dominant electron‐loss mechanism at high plasma densities.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::3fb069a8476f0b7d093cdb0720ab59a2 https://doi.org/10.1063/1.352038 Zobrazit plný text záznamu