An x-ray source generated by an electron beam produced using a Self-Modulated Laser Wakefield Accelerator (SM-LWFA) is explored for use in high energy density science facilities. By colliding the electron beam, with a maximum energy of 380 MeV, total charge of >10 nC and a divergence of 64 × 100 mrad, from a SM-LWFA driven by a 1 ps 120 J laser, into a high-Z foil, an x/gamma-ray source was generated. A broadband bremsstrahlung energy spectrum with temperatures ranging from 0.8 to 2 MeV was measured with an almost 2 orders of magnitude flux increase when compared with other schemes using LWFA. GEANT4 simulations were done to calculate the source size and divergence.
Flying focus is a technique that uses a chirped laser beam focused by a highly chromatic lens to produce an extended focal region within which the peak laser intensity can propagate at any velocity. When that intensity is high enough to ionize a background gas, an ionization wave will track the intensity isosurface corresponding to the ionization threshold. We report on the demonstration of such ionization waves of arbitrary velocity. Subluminal and superluminal ionization fronts were produced that propagated both forward and backward relative to the ionizing laser. All backward and all superluminal cases mitigated the issue of ionization-induced refraction that typically inhibits the formation of long, contiguous plasma channels.
X-ray photon beams in the keV to MeV energy range are essential to study high energy density (HED) matter and to improve the understanding of inertial confinement fusion and astrophysical systems. HED experiments produce highly transient matter under extreme states of temperatures and pressures and it is essential to develop light sources that are: in the hard x-ray energy range (0.01-1 MeV), directional, high-yield, low-divergence, and short-duration (ps and sub-ps). In this work we show that by using a laser plasma accelerator (LPA) driven by a kJ-ps class laser it is possible to generate a broadband (0.01-1 MeV) hard x-ray source that satisfies the previous requirements. A series of experiments were conducted on the Titan laser at Lawrence Livermore
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