Microscopic heterodyne interferometry for determination of electron density in high-pressure microplasma

作者：Urabe Keiichiro^*; Muneoka Hitoshi; Stauss Sven; Terashima Kazuo

来源：Plasma Sources Science and Technology, 2014, 23(6): 064007.

DOI：10.1088/0963-0252/23/6/064007

• interferometry
• microplasma
• electron density

Electron density is paramount for understanding plasma characteristics and for control in plasma applications. To determine the electron density in a plasma by the use of interferometry, the phase shift of a probing electromagnetic (EM) wave induced by interaction with the plasma is measured. In this paper, for the determination of electron density in microplasmas generated under conditions of fluid density higher than that of ambient air, we discuss appropriate wavelength ranges for the probing EM wave (laser beam) in interferometry with consideration of the plasma parameters in the tested plasma source. On the basis of the discussion, we develop an interferometry system using a near-infrared diode laser in combination with a reflection system and a microscope for microplasma diagnostics, and measure the electron density in a 200 ns short-pulse microdischarge generated in a 0.3MPa helium supercritical fluid.

• 出版日期2014-12