Magnetic turbulence in a table-top laser-plasma relevant to astrophysical scenarios

Abstract

Turbulent magnetic fields abound in nature, pervading astrophysical, solar, terrestrial and laboratory plasmas. Understanding the ubiquity of magnetic turbulence and its role in the universe is an outstanding scientific challenge. Here, we report on the transition of magnetic turbulence from an initially electron-driven regime to one dominated by ion-magnetization in a laboratory plasma produced by an intense, table-top laser. Our observations at the magnetized ion scale of the saturated turbulent spectrum bear a striking resemblance with spacecraft measurements of the solar wind magnetic-field spectrum, including the emergence of a spectral kink. Despite originating from diverse energy injection sources (namely, electrons in the laboratory experiment and ion free-energy sources in the solar wind), the turbulent spectra exhibit remarkable parallels. This demonstrates the independence of turbulent spectral properties from the driving source of the turbulence and highlights the potential of small-scale, table-top laboratory experiments for investigating turbulence in astrophysical environments.

Helicity Dynamics, Inverse, and Bidirectional Cascades in Fluid and Magnetohydrodynamic Turbulence: A Brief Review

“…Reconnection is also present in numerous numerical studies (see, e.g., Higashimori et al, ; Karimabadi et al, ; Loureiro et al, ; Mininni et al, ; Ting et al, ; Zhou et al, ) and in plasma relaxation processes (Taylor, ). Finally, there are recent indications, using small‐scale laboratory experiments, that the source of the turbulence may not matter in the resulting spectral dynamics of such MHD flows (Chatterjee et al, ).…”

Probing ultrafast magnetic-field generation by current filamentation instability in femtosecond relativistic laser-matter interactions

“…Experimental evidence for the development of the CFI in relativistic laser-driven plasmas has been mainly provided through characterization of the spatial profiles of the fast electron [33][34][35][36] or ion [24][25][26]37,38] beams exiting the target. In situ measurements of the magnetic-field fluctuations at the irradiated target surface have been performed using optical polarimetry [39,40], yet this technique cannot access the volumetric distribution of the fields, and the data obtained so far could not capture their femtosecond timescale dynamics. Probing plasma electromagnetic fields by an ultrashort electron beam was previously exploited to image plasma wakefields in a laser wakefield accelerator (LWFA) [41] or large-scale inductively generated magnetic fields in target normal sheath acceleration [42].…”

Time-resolved measurements of fast electron recirculation for relativistically intense femtosecond scale laser-plasma interactions

“…Some previous publications have presented evidence of lateral energy transport, commonly attributed to fast electron transport, although under different conditions 19 , 20 , 49 . A number of papers have reported on radial energy transport on femtosecond timescales at the target front surface during high intensity laser-plasma interactions 50 – 52 where strong fields associated with the laser focal spot dominate transport. Metskes et al .…”