Generation of Secondary Particles from Subnanosecond Laser Irradiation of Targets at Intensities of 10^16 W/cm^-2

none15J.Krasa; D.Margarone; D.Klir; A.Velyhan; A.Picciotto; E.Krousky; K.Jungwirth; J. Skala; M.Pfeifer; J. Ullschmied; J.Kravarik; K.Rezac; P.Kubes; P.Parys; and L.RycJ., Krasa; D., Margarone; D., Klir; A., Velyhan; Picciotto, Antonino; E., Krousky; K., Jungwirth; J., Skala; M., Pfeifer; J., Ullschmied; J., Kravarik; K., Rezac; P., Kubes; P., Parys; L., Ry

New methods for high current fast ion beam production by laser-driven acceleration

An overview of the last experimental campaigns on laser-driven ion acceleration performed at the PALS facility in Prague is given. Both the 2 TW, sub-nanosecond iodine laser system and the 20 TW, femtosecond Ti:sapphire laser, recently installed at PALS, are used along our experiments performed in the intensity range 10^16−10^19 W/cm2. The main goal of our studies was to generate high energy, high current ion streams at relatively low laser intensities. The discussed experimental investigations show promising results in terms of maximum ion energy and current density, which make the laser-accelerated ion beams a candidate for new-generation ion sources to be employed in medicine, nuclear physics, matter physics, and industry. © 2012 American Institute of Physics

Confirmation of the topology of the Wendelstein 7-X magnetic field to better than 1:100,000

Fusion energy research has in the past 40 years focused primarily on the tokamak concept, but recent advances in plasma theory and computational power have led to renewed interest in stellarators. The largest and most sophisticated stellarator in the world, Wendelstein 7-X (W7-X), has just started operation, with the aim to show that the earlier weaknesses of this concept have been addressed successfully, and that the intrinsic advantages of the concept persist, also at plasma parameters approaching those of a future fusion power plant. Here we show the first physics results, obtained before plasma operation: that the carefully tailored topology of nested magnetic surfaces needed for good confinement is realized, and that the measured deviations are smaller than one part in 100,000. This is a significant step forward in stellarator research, since it shows that the complicated and delicate magnetic topology can be created and verified with the required accuracy