Generation of disc-like plasma from laser-matter interaction in the presence of a strong external magnetic field

Abstract

Dynamics of laser produced plasma in a strong magnetic field was studied using a 1 MA pulsed power generator coupled to an intense, high-energy laser. A 2-2.5 MG magnetic field was generated on the surface of a rod load 0.8-1.2 mm in diameter. A sub-nanosecond laser pulse with intensity of 3×10 15 W cm −2 was focused on the rod load surface. Side-on laser diagnostics showed the generation of two collimated jets 1-3 mm long on the front and rear sides of the load. End-on laser diagnostics reveal that the laser produced plasma in the MG magnetic field takes the form of a thin disc as the plasma propagates along the magnetic field lines. The disc-like plasma expands radially across the magnetic field with a velocity of 250 km s −1 . An electron temperature of 400 eV was measured in the laser-produced plasma on the rod load.

Enhanced X-ray emission arising from laser-plasma confinement by a strong transverse magnetic field

“…2 b,c). This global morphology is consistent with previous observations 30 , 31 , 33 , 34 . Extending these previous studies, we can observe in Fig.…”

“…4 and 10 of that paper). In stark contrast, when applying the external magnetic field, we observe that the plasma is focused on axis by the magnetic tension into a conical shape, from which emerges a slab 33 , 34 which is observed by the optical (Fig. 2 b,c) and X-ray diagnostics (see Fig.…”

“…From early snapshots of the interferometry diagnostics (not shown), we observe that the cavity already starts to form at ns, and that the slab emerges from the cavity at 8 ns. The slab is formed as the plasma is able to expand along the magnetic field lines (in the XZ plane), but is highly compressed and modulated 33 , 34 in the XY plane (see Fig. 2 b,c).…”

“…Here we will focus on the dynamics of the plasma expansion as illustrated in Fig. 1 , with the aim to not characterize the long-range plasma propagation as was done before 30 , 31 , 33 – 35 , but the dynamics near the wall itself. Consistent with previous studies, we observe that in its initial launching at the target surface, the plasma has a ratio (where is the overall plasma pressure, i.e.…”

Laboratory modelling of equatorial ‘tongue’ accretion channels in young stellar objects caused by the Rayleigh-Taylor instability

“…We note that the configuration in which a plasma stream propagates across a magnetic field has long been experimentally investigated (see e.g., Sucov et al 1967;Bruneteau et al 1970;Plechaty et al 2013;García-Rubio et al 2016;Ivanov et al 2017;Tang et al 2018;Khiar et al 2019;Leal et al 2020;Filippov et al 2021). The most recent studies Plechaty et al (2013), García-Rubio et al (2016), Ivanov et al (2017), Tang et al (2018), Khiar et al (2019), and Leal et al (2020), investigated the overall plasma dynamics in such a configuration and revealed that the plasma is able to extend along the magnetic field with a plasma slab-like global morphology, where the plasma is being compressed by the magnetic field into a thin layer in the plane that contains the magnetic field. The specificity of our work with respect to the abovementioned studies is that here the surface of the target affected by laser irradiation is very large.…”