Wire array experiments in a low impedance and low current generator

15th Latin American Workshop on Plasma Physics; 21st IAEA TM on Research Using Small Fusion Devices

Cabrini, Nibaldo^3 ; Pavez, Cristian^1,2,3 ; Avaria, Gonzalo^1,2 ; Martin, Patricio San^1 ; Veloso, Felipe^5 ; Zúñiga, Barbara^4 ; Sepúlveda, Adolfo^4 ; Soto, Leopoldo^1,2,3

Comisión Chilena de Energía Nuclear, Chile^1

Center for Research and Applications in Plasma Physics and Pulsed Power - P4 Chile, Chile^2

Departamento de Ciencias Físicas, Universidad Andrés Bello, Chile^3

Facultad de Ingeniería, Universidad Mayor, Santiago, Chile^4

Instituto de Física, Pontificia Universidad Católica de Chile, Santiago, Chile^5

关键词: Charging voltage;    Current derivatives;    Load impedance;    Load resistances;    Multi-purpose;    Parallel wires;    Rogowski Coil;    Schlieren techniques;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/591/1/012026/pdf
DOI  :  10.1088/1742-6596/591/1/012026

来源: IOP

【 摘 要 】

In this work, a preliminary study about the behavior of a low impedance generator on different wire array configurations is reported. The experimental measurements were carried out on a small multi-purpose generator (1.2μF, 345J, 47.5nH, T/4 = 375 ns and Z = 0.2Ω in short circuit) which produces currents up to 122 kA with 500 ns quarter period, when a charging voltage of 24kV and a wire load are used. Two types of configurations were tested: parallel wires (two and four) and X-pinch configurations. The experiments were carried out on W, Al, and Cu wires with different diameters. The discharge was characterized by means of a set of diagnostics which included: Rogowski coil; filtered PCD detector; filtered PIN diode; gated VUV/soft X-ray pinhole camera, Shadow diagnostic and dark field Schlieren technique. From the set of experimental results, the following observations can be established: (i) The generator is highly sensitive to the changes of load impedance due to its low impedance design. (ii) Every shot shows a dip in the current derivative signal shortly after the discharge onset time (from 6 to 40 ns), which is inversely related to the load resistance. (iii) Both configurations show a similar dynamic to those observed in experiments of higher current and shorter quarter period. (iv) At the X-pinch experiments, two or more hard X-ray bursts are detected, around 200 ns from the current onset time. These X-ray bursts are correlated with the dips observed in the current derivative signal.