A fusion-grade 20-MA liner-on-plasma implosion system without preheat and premagnetization

Abstract

“Cold-start” one-dimensional magnetohydrodynamic computations identify a set of parameters (liner mass, fuel mass, liner/fuel interface radius, etc.) that show that a simple z-pinch-driven liner-on-plasma implosion system, without preheating or premagnetization, can reach fusion temperature with a 20-MA, 100 ns electrical current drive at a possibly achievable radial convergence level (∼30). The calculations demonstrate the complex behavior of a solid liner as it explodes initially, followed by a reassembly that implodes inward and compresses the fuel. The calculations illustrate the behavior of the strong shock launched in the fuel by the liner and show the shock reflected off the liner dissipates to a sound wave as the post-shock fusion fuel is quasi-adiabatically heated to fusion temperatures. The calculations examine the competition between the simultaneous heating and cooling mechanisms that determine whether a magnetically driven liner can heat the fuel to fusion temperature. The behavior of different liner materials is studied. A high-current (60 MA) configuration that potentially could reach high gain is reported, as is a corresponding system using a xenon gas-puff as the liner.