Study of Shock-Compressed Argon Plasma Using Microwave Diagnostics
- PDF / 851,867 Bytes
- 7 Pages / 612 x 792 pts (letter) Page_size
- 11 Downloads / 171 Views
Study of Shock-Compressed Argon Plasma Using Microwave Diagnostics E. N. Bogdanova , M. V. Zhernokletova , G. A. Kozlova , and A. V. Rodionova
UDC 533.7
Published in Fizika Goreniya i Vzryva, Vol. 56, No. 4, pp. 121–127, July–August, 2020. Original article submitted June 24, 2019; revision submitted September 25, 2019; accepted for publication November 6, 2019.
Abstract: A microwave diagnostics method and radio interferometers with wavelengths of 3.2 and 2.1 mm are used to study the kinematic and electrophysical characteristics of shock-compressed argon plasma, which is initially at atmospheric pressure. This research study is carried out at pressures of 12–56 MPa, shock wave velocities of 3.1–6.2 km/s, temperatures 9000–19 000 K, and densities 0.006–0.012 g/cm3 for powers of Coulomb nonideality from 10−4 to 0.2. The data obtained on the shock-wave compressibility of argon are consistent with the known measurement results and calculations using the modified van der Waals model and the chemical plasma model. A set of values of the reflection coefficient of electromagnetic radiation from the shock wave front at wavelengths of 3.2 and 2.1 mm is obtained, which serves as a basis for estimating the conductivity and electron concentration behind the shock wave front. The experimental data are consistent with calculation results in a wave velocity range of 3.1–3.6 km/s. It is established that with a further increase in the velocity has no effect on the reflection coefficient. Keywords: argon, collisional plasma, microwave diagnostics. DOI: 10.1134/S0010508220040127
INTRODUCTION One of the methods for studying the properties of plasma generated by the action of powerful shock waves on matter is microwave (radio interferometric) diagnostics [1]. These methods are based on the reflection of probe microwave radiation from a shock wave front in gases, which is caused by ionization and high conductivity of compressed and heated matter behind the front. In [2], the effect of the conductivity of a shockcompressed gas on recording a liner velocity by Doppler nonperturbing diagnostics was studied. Conductivity estimates for air and helium behind a shock wave (SW) front obtained using a microwave interferometer indicated the existence of threshold values of the liner velocity, above which radio emission was reflected from a
the SW front in the gas. Thus, the radio interferometer recorded the SW motion in the gas and not the liner surface. The studies carried out in [2] demonstrated the possibility of obtaining information on the kinematic and electrophysical parameters of the shock-compressed gas plasma. The goal of this study is to determine the shockwave compressibility parameters of gaseous argon and the reflection coefficients of millimeter-wave radiation from the SW front in argon. The choice of argon is due to the availability of experimental and calculated information on its shock-wave compressibility and conductivity behind the SW front. In this study, argon was initially at atmospheric pressure and a temperature T0 = 273 K.
All-Russi
Data Loading...
