Simulations of the Interaction of High-Velocity Condensed-Matter Liners With Walls

This paper presents an overview of publications on numerical simulations of one of the major 2-D effects observed in magnetically driven implosion of cylindrical condensed-matter liners: their interaction with glide planes. We consider liners accelerated to 8-20 km/s by currents of 30-100 MA delivered by disk explosive magnetic flux compression generators with azimuthal magnetic fields of 1-6 MG (magnetic pressures of 0.04-1.4 Mbar): experimental liners HEL-1, ALT-1, 2, and liners HEL-2, ALT-3 proposed for high energy density physics research.

I. Introduction

Implosion of cylindrical condensed-matter liners driven by azimuthal magnetic fields is used and simulated for multiple purposes [1]– [22], for example, compression of axial magnetic fields to amplify them [1]; materials strength measurements based on the growth of perturbations [2], [6], [11]; isentropic compression of materials to 10 Mbar [11], [22]; analysis of shock dynamics in layered systems [7]; studies of liner instabilities and interaction of liners with glide planes [3]–[21] (see Fig. 1 [4], Fig. 2 [11]); and generation of 5–30 Mbar pressures to measure Hugoniots of materials, as in the ALT-1, 2 [9] and HEL-1 [10] experiments and in the HEL-2 [3], [8], [11] and ALT-3 [13] projects. In these experiments, the liner typically implodes on a central target, except for the magnetic field compression experiments [1] (see Table I).TABLE I Implosion Parameters of Experimental Al Liners

Liner	cm	cm	cm	cm
[1]	2.9	0.1	0.15	8.5	26.5	0.3
NTLX [7]	5.0	0.1	2.0	4.0	29	0.7
LT-1 [4]	3.0	0.1	0.6	2.4	23	1
Pegasus [2]	2.4	0.04	>0.6	2.0	<44	<0.9
[22]	0.343	0.153	0.05	0.9	0.9	0.16
HEL-1 [10]	24	0.4	5.5	10	45	1.8
ALT-1,2 [9]	4.0	0.2	1.0	4.0	14	0.7

Liner	g/cm	MA		MG	km/s	(Z) degrees
[1]	4.8	9.5	5	1.5	0	6
NTLX [7]	8.4	16	5	0.8	6	10
LT-1 [4]	5.0	5	40	1	5	2–8(Cu)
Pegasus [2]	1.6	>4	4.5	>1	>4.2	8
[22]	1.14	16	0.8	16	20	45(Ta)
HEL-1 [10]	160	105	40	1	8	6 (Fe)
ALT-1,2 [9]	13	31	2	2	12	8 (Cu)

Designations in Table I: and are the outer and the impact linear radius and impact velocity (in [1], the liner is stopped by magnetic field pressure); and are the liner height and thickness (in [22], the liner has two layer, 0.1mm Al + 0.053mm Cu); is the liner mass per unit lenght; and are the peak current and the rise time from 0.1 to 0.9 of is the maximum magnetic field on the liner surface; (Z) = const is the wall slope (material), see Fig. 1.

Fig. 1.

LT-1 EMG experiment. (a) Radiograms and (b) 2-D HD implosion simulations of two liners with wall slopes and 8°.

Fig. 2.

2-D MHD simulation of a prototype MAGO chamber proposed for magnetized plasma compression (the RUS-8 project: cm, mm; MA, , Atlas facility).