Measurements of ultrastrong magnetic fields during relativistic laser–plasma interactions

Abstract

Measurements of magnetic fields generated during ultrahigh intensity (>1019 W cm−2), short pulse (0.7–1 ps) laser–solid target interaction experiments are reported. An innovative method is used and the results are compared with particle-in-cell simulations. It is shown that polarization measurements of the self-generated harmonics of the laser can provide a convenient method for diagnosing the magnetic field—and that the experimental measurements indicate the existence of peak fields greater than 340 MG and below 460 MG at such high intensities. In particular, the observation of the X-wave cutoffs and the observed induced ellipticity of the harmonics can provide a reliable method for measuring these fields. These observations are important for evaluating the use of intense lasers in various potential applications and perhaps for understanding the complex physics of exotic astrophysical objects such as neutron stars.

Scaling Laws for Collisionless Laser–Plasma Interactions of Relevance to Laboratory Astrophysics

“…A variety of mechanisms for generation of a quasi-static magnetic field have been discussed in the past, including the thermo-electric dynamo [17] and a ponderomotive force [18]. These mechanisms easily explain the appearance of the toroidal magnetic field, as shown in Fig.…”

Self-consistent model of electron drift mode turbulence

“…On the other hand, since the end of the 1970s, experiments have demonstrated that strong quasi-steady magnetic fields are created in laser-produced plasmas [19]. This was an important result as it had often been assumed that the absence of magnetic field effects, which greatly affect heat transport, was a desirable feature of laser-produced plasmas [20].…”

On the modulational stability of magnetic structures in electron drift turbulence

“…[7][8][9][10] Also, since the end of the 1970s, experiments have shown that strong quasisteady magnetic fields are created in laser-produced plasma. 11 This was an important result as it had often been assumed that the absence of magnetic field effects, which greatly affect heat transport, was a desirable feature of laser-produced plasmas. 12 These measurements showed clearly that strong magnetic fields can be generated even in unmagnetized plasmas.…”