Analyses of spatiotemporal dynamic behavior of microplasmas based on three-dimensional diagnostics

点击翻译按钮获取中文摘要

The major roll of our group in the whole project was to develop diagnostic methods in the gas phase for plasma parameters and active species in various types of microplasmas with sufficient spatiotemporal resolutions. As the targets, firstly, we selected a single discharge cell of a plasma display panel (PDP) and performed a three-dimensional measurement of excited atoms in the unit cell by using a specially designed structure combined with a diode-laser absorption spectroscopy technique. We applied also a similar method to the diagnostics in an array of microplasmas for a large area atmospheric pressure plasma source. For the electron density n_e, we developed a diagnostic method using microwaves in the frequency range of 10 to 100 GHz, and obtained average values of n_e in space for planar microplasma arrays with a good temporal resolution. As a complementary method, we constructed a heterodyne interferometer using a CO_2 laser of 10.6 μm wavelength. It has a spatial resolution better than 0.1 mm although the temporal resolution is instrumentally limited up to a few tens of microseconds. We also developed also a THz time-domain spectroscopy (TDS) method for the simultaneous measurement of n_e and the collision frequency v_e through the effective complex dielectric function of microplasma arrays.On the other hand, we directed our objective toward the creation of new functions with microplasmas utilizing their inherent properties. As such examples, we developed several types of plasma photonic crystals for controlling microwaves of mm to sub-mm ranges. Another direction is the generation of microplasmas in heterogeneous media such as microdischarge in bubbles under water. We tested a fabric electrode structure immersed in water to generate bubbles on the surface by electrolysis, and ignited discharge in those bubbles containing H_2 or O_2.