HOT PHOTOLUMINESCENCE STUDY OF MINIBAND EFFECTS IN GaAs/AlAsSLs

We report the study of the effect of miniband width on polarization properties of the hot electron photoluminescence (HPL) in SLs . It is demonstrated that the energy and magnetic field dependencies of the HPL polarization are very sensitive to the electron miniband widths. We show that high magnetic field applied perpendicular to the SL growth direction (Voigt geometry) induces transition (magnetic field breakdown) between electron minibands. The vertical transport of spin polarized and momentum aligned hot electrons is studied.

Download Full-text

Collimation of hot electron beams by external field from magnetic-flux compression

Laser and Particle Beams ◽

10.1017/s026303461300044x ◽

2013 ◽

Vol 31 (4) ◽

pp. 579-582 ◽

Cited By ~ 3

Author(s):

Yuqiu Gu ◽

Jinqing Yu ◽

Weimin Zhou ◽

Fengjuan Wu ◽

Jian Wang ◽

...

Keyword(s):

Magnetic Field ◽

Electron Beam ◽

External Magnetic Field ◽

Magnetic Flux ◽

External Field ◽

Fast Ignition ◽

Hot Electrons ◽

Hot Electron ◽

Flux Compression ◽

Magnetic Flux Compression

AbstractIn fast ignition of inertial confinement fusion, hot electron beam is considered to be an appropriate energy source for ignition. However, hot electrons are divergent as they are transporting in over-dense plasma. So collimating the hot electrons becomes one of the most important issues in fast ignition. A method to collimate hot electron beam by external magnetic field is proposed in this paper. The external field can be generated by compressing a seed magnetic field at the stage of laser-driven implosion. This method is confirmed by particle-in-cell simulations. The results show that hot electrons are well collimated by external magnetic field from magnetic-flux compression.

Download Full-text

Imposed magnetic field and hot electron propagation in inertial fusion hohlraums

Journal of Plasma Physics ◽

10.1017/s0022377815001348 ◽

2015 ◽

Vol 81 (6) ◽

Cited By ~ 13

Author(s):

David J. Strozzi ◽

L. J. Perkins ◽

M. M. Marinak ◽

D. J. Larson ◽

J. M. Koning ◽

...

Keyword(s):

Magnetic Field ◽

Inertial Confinement Fusion ◽

Stimulated Raman Scattering ◽

Axial Magnetic Field ◽

Early Time ◽

Hot Electrons ◽

Hydrodynamic Effect ◽

Test Case ◽

Inertial Confinement ◽

Hot Electron

The effects of an imposed, axial magnetic field $B_{z0}$ on hydrodynamics and energetic electrons in inertial confinement fusion indirect-drive hohlraums are studied. We present simulations from the radiation-hydrodynamics code HYDRA of a low-adiabat ignition design for the National Ignition Facility, with and without $B_{z0}=70~\text{T}$. The field’s main hydrodynamic effect is to significantly reduce electron thermal conduction perpendicular to the field. This results in hotter and less dense plasma on the equator between the capsule and hohlraum wall. The inner laser beams experience less inverse bremsstrahlung absorption before reaching the wall. The X-ray drive is thus stronger from the equator with the imposed field. We study superthermal, or ‘hot’, electron dynamics with the particle-in-cell code ZUMA, using plasma conditions from HYDRA. During the early-time laser picket, hot electrons based on two-plasmon decay in the laser entrance hole (Regan et al., Phys. Plasmas, vol. 17(2), 2010, 020703) are guided to the capsule by a 70 T field. Twelve times more energy deposits in the deuterium–tritium fuel. For plasma conditions early in peak laser power, we present mono-energetic test-case studies with ZUMA as well as sources based on inner-beam stimulated Raman scattering. The effect of the field on deuterium–tritium deposition depends strongly on the source location, namely whether hot electrons are generated on field lines that connect to the capsule.

Download Full-text