Push and pull magnetic reconnection driven by intense laser interaction with double-coil capacitor target

Abstract

Push and pull magnetic reconnection (MR) experiments using a high-power laser irradiating a capacitor target with the plates connected by a pair of coils are carried out. During the beginning (end) stages of the laser-target interaction that creates a hot plasma in the region, the rise (fall) of the coil currents generates expanding (contracting) magnetic fields that reconnect in the mid-plane between the coils, resulting in push (pull) MR. Proton radiography and proton ray-tracing simulation are used to track the evolution of the magnetic field distribution. The proton aggregate and void characteristics between the coils are related to the opposite current-sheet current during the push and pull MR stages. The directions of the hot plasma electron outflows during these two MR phases are obtained by monitoring the soft X-ray emission. Our results suggest that the double-coil capacitor target may be useful for laboratory modeling of fast MR and related phenomena in astrophysical plasmas.

Narrow-bandwidth, extreme ultraviolet, spontaneous light-imaging technique for laser-driven magnetic reconnection studies

“…As another example, we tried to diagnose a low-𝛽 configuration LDMR, as shown in figure 7. A capacitor-coil target with a double-U-turn Helmholtz coil [24]- [27] was used. A nanosecond laser was irradiated on the rear disc through the centre hole of the front disc, and the generated electrons scattered and impinged on the inner surface of the front disc; this generated a potential difference between the two discs.…”

“…In the experiment, the diagnostic technique of proton radiography was also performed using proton beams to measure the dual-coil region of the LDMR [27]. The proton beam was generated in the XG-III laser facility by driving a gold thin film target with an ultra-intense, ultra-short laser with a wavelength of 1053 nm, duration approximately equal to 1 ns, and energy approximately equal to 100 J.…”