7th International Conference on Matter and Radiation at Extremes (ICMRE2024)

If the 100-tesla level of magnetic field is used as a seed field, which could be generated with laser-driven capacitor-coil setup [1], the semi-static magnetic field as strong as 104~105 tesla is possible from simulation with the method of  laser-driven magnetic-flux compression [2]. In this way, the experimental investigation of whistle mode for high-energy CO2 laser or Nd:YAG laser become possible, where the strength of magnetic field must be higher than a value of Bc(tesla)=1.07×104λμm-1 [3]. The above developments have profound impact on the research of inertial confinement fusion, since it becomes possible, for the first time, to deposit energy of fusion laser to the compressed fuel, not relying on the shock waves or secondary electron/ion beams.

The author has studied the related theory in the past 5 years [3], especially the collisional heating of the highly magnetized over-dense plasma in the whistler mode with nanosecond right-hand circularly polarized (RHCP) laser at moderate intensity. It is found that the plasma with density of 1023cm-3 and initial temperature of 100 eV could be heated up to more than 1000 eV with depth of around 20 micrometers in 1 nanosecond using RHCP Nd:YAG laser at intensity of 1014Wcm-2, if the strength of magnetic field is as high as 100 kilotesla [4]. The dependences of heating depth and temperature on parameters of laser, magnetic field and plasmas are also studied, resulting in a scaling law [5].  It is also found that the over-dense plasma in such situation could be diagnosed with optical laser probing beam, other than x-ray beam, where the density/temperature of plasma and the strength of strong magnetic field could be measured [6]. Recently, the above characters are also extended to situations of inhomogeneous plasma density to mimic the conditions of real experiment. In the presentation, the author will also give the preliminary discussions on the possibility of  direct laser ignition scheme for inertial confinement fusion in the whistler mode, for the first time to the knowledge of the author, which includes the effect of cyclotron energy loss, energy required to generate the 104~105 tesla level of magnetic field and the possible direct ignition schemes.
 

Whistler-mode waves,ignition,,highly-magnetized,over-dense plasma