Application of eclipse laser photodetachment technique to electron sheath thickness and collection region measurements

The laser photodetachment (LPD) technique, was applied for the measurement of electron sheath thickness and the collection region of photodetached electrons (PDE's). The electron sheath thickness around a plane probe and a cylindrical probe was measured in two kinds of magnetic fields. The electron collection region of photodetached electrons was also measured from the shadow position dependence of the LPD signal intensity. It was observed that the laser photodetachment signal intensity is reduced when the collection region is longer than the laser radius, and the recovery time is reduced when the electron sheath thickness is considerably thick.