• Rosenzweig, J. B.
• Karger, O.
• Hidding, Bernhard
• Königstein, T.
• Pretzler, G.

Abstract

Laser-plasma-accelerators are relatively new accelerator devices which are characterized by being very compact, which is the result of the giant electric accelerating fields present in strongly focused, high-power ultrashort laser pulses. Peak intensities of modern laser systems can reach $10^{22}\,{W/cm^2}$ or more, which is many orders of magnitude larger than the complete sunlight incident on Earth, if it were collected and focused at the same time onto an area of a tip of a pencil. Such intensities make such laser systems attractive for many applications, as exotic as inertial confinement fusion and producing ultrashort electron beams with GeV-scale energies or advanced light sources such as free-electron lasers, or those based on inverse Compton scattering and betatron radiation. The woldwide booming community in this fields works towards these applications which have highly stringent demands on beam quality, as an alternative to well-established accelerators based on radiofrequency cavity based accelerators such as linacs (for electrons) and cyclotrons (for protons and ions). Breakthroughs were achieved in 2004, when for the first time instead of spectrally very broadband and rather divergent particle beams, pencil-like electron beams with quasi-monoenergetic electron bunch distribution were generated. Beam quality in terms of narrow energy spread and larger energies (beyond the GeV barrier) improves continuously and rapidly, fueled by progress in terms of understanding and by ever increasing laser power and technology readiness. In contrast to such highest-quality beams which are needed for example for free-electron-lasers, space radiation which harms electronics and living systems outside Earth's protective magnetic fields, is always very broadband. In fact, conventional accelerators always automatically produce very narrowband particle beams, which are unnatural.It has been proposed (and patented) for the first time in 2009 to use compact laser-plasma-accelerators to produce broadband radiation such as present in space and to use this for radiation hardness tests. Such broadband radiation is the inherent regime of laser-plasma-accelerators. The difficulty of laser-plasma-accelerators to produce monoenergetic beams is turned into a noted advantage here. Since producing broadband radiation is possible since many years with laser-plasma-accelerators, thisapplication is one which has been ''left behind'' for many years now due to the community seeking to produce more monoenergetic beams such as with conventional accelerators. <br/><br/>Recent proof-of-concept experiments in a project which merged state-of-the-art space radiation testing with state-of-the-art laser-plasma acceleration hasshown that by using laser-plasma-accelerators it is possible to reproduce the spectral characteristics of radiation belt ''killer electrons'' for example, which populate the radiation belts on GEO orbits, for instance. This especially prominent type of space radiation was for the first time produced in the laboratory here on Earth in a well-controlled mannerand seems to be a a natural candidateas a benchmark for other radiation sources, which produce monoenergetic beams based on which also the use of degraders cannot reproduce space radiation which is characterized by a decreasing (often exponentially decreasing) spectral flux towards higher particle energies. Spectral flux shaping by tuning the laser-plasma-interaction parameters has been demonstrated, for example to reproduce the electron flux incident on satellites on GPS orbits according to the AE8 model. Sophisticated diagnostics, readily available from the laser-plasma-community as well as the traditional accelerator community, which are increasingly merging (again), have been used to characterize and monitor the flux. State-of-the-art radiation hardness testing techniques have been adapted to the laser-plasma radiation source environment, test devices have been exposed to laser-plasma-generated space radiation and it was shown that the performance of these electronic devices was degraded. With the exception of doing radiation tests directly in space, these irradiation campaigns may have been the most realistic space radiation tests to be carried out in the laboratory here on Earth to date. The approach of reproducing space radiation flux directly in the lab has hitherto not been accessible, which is why approximative techniques employing monoenergetic beams had to be used. This clearly demonstrated the applicability of laser-plasma-accelerators for space radiation reproduction, and is currently triggering large interest in the laser-plasma-community. Other advantages of laser-plasma-accelerators are that they can produce electrons, protons and ions alike -- even at the same time --as well as enormous peak flux, which may allow for exploration of nonlinear response of electronics and biological systems. <br/><br/>Both fields, laser-plasma-acc...

Topics

• impedance spectroscopy
• experiment
• hardness
• hardness testing