Use of a double-Wollaston prism laser differential interferometer in a plasma focus

Journal Article · Sat Feb 01 00:00:00 EST 1997 · Review of Scientific Instruments

DOI:https://doi.org/10.1063/1.1147871· OSTI ID:450584

Lu, M F ^[1]

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1. Institute of Physics, Chinese Academy of Sciences, Beijing 100080, Peoples Republic of (China)

A double-Wollaston prism laser differential interferometer (LDI) has been developed to observe, for the first time, the evolution of the imploding current sheath (CS) and the high temperature and high density plasma pinch in the plasma focus. The light source is a Q-switched and frequency-doubled YAG laser operated in a single-pulse mode: {lambda}=532 nm, the pulse width (FWHM) about 10 nm (also the resolution time of the LDI). The LDI measures density gradients and has a line sensitivity of about n{sub e}{sup {prime}}=(2.58{plus_minus}0.46){times}10{sup 25} m{sup {minus}4} for a typical sheath thickness of 1.6 mm and a minimum distinguishable fringe shift of 5{percent}, and a spatial resolution of 1.26 mm. The density gradient and equivalent density of the CS are measured to be n{sub e}{sup {prime}}{approx}(2.58{plus_minus}0.46){times}10{sup 26} m{sup {minus}4} and n{sub e}{approx}(3.25{plus_minus}0.59){times}10{sup 23} m{sup {minus}3}, respectively. More importantly in this article, the double-Wollaston prism LDI, with a simple optical arrangement, gives direct physical pictures of the high density gradient plasma configuration and structure which are of interest in studying the status of plasma motion. {copyright} {ital 1997 American Institute of Physics.}

• OSTI ID: 450584
• Journal Information: Review of Scientific Instruments, Vol. 68, Issue 2; Other Information: PBD: Feb 1997
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION
PLASMA FOCUS
PLASMA DIAGNOSTICS
PLASMA SHEATH
PINCH EFFECT
INTERFEROMETERS
PLASMA FOCUS DEVICES
PRISMS
LASER RADIATION
PLASMA DENSITY