Numerical analysis of pulsed magnetic field diffusion dynamics in gold cone target

Abstract

Strong magnetic fields from a few hundred to a thousand tesla have been produced in a laboratory by using high-intensity laser beams. This strong magnetic field in a laboratory becomes a powerful tool to perform experiments in the fields such as laboratory astrophysics and nuclear fusion research. The diffusion dynamics of a pulsed magnetic field in a target is a key phenomenon for experiments with the laser-produced magnetic field. Here, we have developed a two-dimensional (2D) electromagnetic dynamics simulation code with consideration of inductive heating to simulate spatiotemporally resolved 2D profiles of the applied magnetic field in a target. The application of an external kilo-tesla-level magnetic field to a gold-cone-attached target is a promising scheme for the enhancement of heating efficiency of the fast-ignition inertial confinement fusion scheme. Our simulation revealed that the magnetic field heats the gold cone due to the inductive heating and penetrates the gold cone during its pulse duration. The developed simulation code is generally useful for designing and analyzing experiments using a strong magnetic field.

Simulating the external magnetic field in short-pulse intense laser-plasma interaction

“…For the calculation we have used ν m = 0.1 m/s 2 . One can see that full magnetization of the plasma occurs on the ns to 10 ns time scale, consistent with that from hydrodynamic simulations and some existing works [10,11,23]. From this point of view, the model using the external field in Case 2 can also be considered as a long-time stationary situation of Case 1, where the plasma is fully magnetized and thus no diamagnetism is observed.…”

“…We see that ν m decreases with the increase of n e , but is only weakly dependent on T e . This result is quite different from that of collision dominated magnetic diffusion, where according to the Spitzer-Harm theory ν m would depend mainly on the electron temperature [23]. Such a discrepancy will be investigated in a future work.…”

“…Therefore, the field felt by plasma particles shall deviate from its vacuum value, which however can not be correctly described by conventional simulations. Recent studies showed that magnetic field penetration into an unmagnetized plasma is on the nanosecond (ns) time scale [10,11,23]. On the other hand, typical SLPI take place within the scale of picoseconds (ps) or less.…”

Electron acceleration in dense plasmas heated by a picosecond relativistic laser

“…collision, ionization, and recombination, in warm dense matters are essential. Cross-section of collisions in warm dense matters is still under discussion [20,21]. For longer time scale interactions over ps with dense, solid density plasmas, collisional heat transport appears even for high intensity laser interactions.…”

Simple Analysis of the Laser-to-Core Energy Coupling Efficiency with Magnetized Fast Isochoric Laser Heating

“…A solid sphere target has been introduced for use with magnetized fast isochoric laser heating to produce a stable core [15] and a moderate guiding field [16][17][18]. We have achieved a maximum laser-to-core energy coupling of 8% [19] even with a relatively small-areal-density core when compared with that used in previous integrated experiments without the application of an external magnetic field [20].…”