Narkis J, Conti F, Velikovich A L, Beg F N
Center for Energy Research, University of California San Diego, La Jolla, California 92093, USA.
Plasma Physics Division, Naval Research Laboratory, Washington, District of Columbia 20375, USA.
Phys Rev E. 2021 Aug;104(2):L023201. doi: 10.1103/PhysRevE.104.L023201.
The gas-puff Z-pinch is a well-known source of x-rays and/or neutrons, but it is highly susceptible to the magneto-Rayleigh-Taylor instability (MRTI). Approaches to MRTI mitigation include density profile tailoring, in which nozzles are added or modified to alter the acceleration trajectory, and axial pre-magnetization, in which perturbations are smoothed out via magnetic field line tension. Here, we present two-dimensional magnetohydrodynamic simulations of loads driven by an 850 kA, 160 ns driver that suggest these mitigation strategies can be additive. The initial axial magnetic field, B_{z0}, to stabilize a 2.5-cm-radius Ne gas liner imploding onto an on-axis deuterium target can be reduced from 0.7 T to 0.3 T by adding a second liner with a radius of 1.25 cm. Because MRTI mitigation tends to increasingly lower yield with higher B_{z0}, the use of a lower field is advantageous. Here, we predict a reduction in yield penalty from >100× with the single liner to <10× with a double liner. A premagnetized, triple nozzle gas puff could therefore be an attractive source for intense neutrons or other fusion applications.
喷气Z箍缩是一种著名的X射线和/或中子源，但它极易受到磁瑞利-泰勒不稳定性（MRTI）的影响。减轻MRTI的方法包括密度分布调整，即添加或修改喷嘴以改变加速轨迹，以及轴向预磁化，即通过磁力线张力消除扰动。在此，我们展示了由850 kA、160 ns驱动器驱动的负载的二维磁流体动力学模拟，结果表明这些减轻策略可以叠加。通过添加一个半径为1.25 cm的第二层衬套，将半径为2.5 cm的氖气衬套向轴上氘靶内爆聚时用于稳定的初始轴向磁场Bz0，可以从0.7 T降低到0.3 T。由于随着Bz0的增加，减轻MRTI往往会导致产率越来越低，因此使用较低的磁场是有利的。在此，我们预测产率损失将从使用单层衬套时的>100倍降低到使用双层衬套时的<10倍。因此，预磁化的三喷嘴喷气可能是产生强中子或用于其他聚变应用的有吸引力的源。
