Rodriguez Prieto, Gonzalo
Highly charged ion jets from medium flux laser plasmas.
Technische Universität, Darmstadt
[Ph.D. Thesis], (2006)
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|Item Type:||Ph.D. Thesis|
|Title:||Highly charged ion jets from medium flux laser plasmas|
The plasma physics group at the Gesellschaft für Schwerionenforschung (GSI) studies the interaction of accelerated heavy ions with dense laser created plasmas with special focus on the energy loss of the ions. Thus experimental characterization of the laser plasmas becomes important, and despite the increased quantity of analytical models and simulations, it still is an active area of research. In experiments made at GSI and other laboratories, the presence of ions with MeV kinetic energies has been found from laser created plasmas with medium laser fluxes of 1011-1012 W/cm2. They were found through measurement of the doppler shift of spectral lines in the X ray range. Experiments performed to establish the conditions of this ion generation are presented here. Large jets of highly charged ions have been produced with the nhelix laser system, while their measured kinetic energies were not larger than 9 keV. The jet length has been measured and resulted to be 4 mm, detected with X ray pinhole cameras and spatially resolved X ray spectrometers. Expansion properties of the quasi-static plasma during the laser pulse and the laser expansion have been compared. The comparison has been made with light emission recorded with a visible spectral range streak camera and an ultraviolet spectrometer from the expanding plasma and the X ray emission from the quasi-static state. The observed jet structure is created when the laser focus is at distances of 0.5 to 1.0 mm in front of the target surface. There is a laser flux threshold for jet generation in the order of 1012 W/cm2, independently of other parameters. Changes in the laser beam angle incidence from normal to non normal lead to an increment of jet length. It is possible to extend these results to the targets suitable for ion beam-laser interaction experiments. The laser absorption in the planar laser-plasma interaction takes place near the critical density in a sheath of nanometers, while the targets have micrometers thickness. The creation of the highly charged ion jets will increase the interaction volume of the ion beam-laser created plasma thus providing a better tool for studying the ions` energy loss.
|Place of Publication:||Darmstadt|
|Divisions:||05 Department of Physics|
|Date Deposited:||17 Oct 2008 09:22|
|Last Modified:||07 Dec 2012 11:52|
|Referees:||Hoffmann, Prof. Dr. Dieter H. H. and Roth, Prof. Dr. Markus|
|Advisors:||Hoffmann, Prof. Dr. Dieter H. H.|
|Refereed:||30 October 2006|