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Tesi etd-01032013-111726


Thesis type
Tesi di dottorato di ricerca
Author
NINDRAYOG, AMRITPAL SINGH
URN
etd-01032013-111726
Title
Ion Acceleration by Solitary and Shock Waves Driven by Laser- Plasma Interactions
Settore scientifico disciplinare
FIS/03
Corso di studi
SCIENZE DI BASE
Commissione
tutor Prof. Pegoraro, Francesco
tutor Prof. Macchi, Andrea
Parole chiave
  • Nessuna parola chiave trovata
Data inizio appello
07/01/2013;
Consultabilità
completa
Riassunto analitico
This thesis presents a theoretical study of the interaction of intense, ultrashort laser pulses with overdense<br>plasmas. Main objectives are to understand the basic phenomenon which leads to the formation<br>of non-linear electrostatic coherent wave structures in form of either solitary ion acoustic waves (SAW)<br>or collisionless shock waves (CSW). These different types of waves have been classified according to<br>Sagdeev’s theory and related formulas have been used for comparison with the numerical results. The<br>particular focus is on the effect on ion acceleration, by means of ion refection by the moving electrostatic<br>field associated to the shocks/solitons. An extensive numerical study by 1D PIC simulations has<br>been performed and in particular the differences arising between linearly polarized pulses and circularly<br>polarized pulses have been discussed. In a cold plasma, ion bunches produced by “hole boring” (HB)<br>radiation pressure acceleration at the target surface may propagate in the bulk as solitary waves. The acceleration<br>mechanism of these ion bunches has been discussed pointing out a distinction between shock<br>acceleration (SA) and HB acceleration, also with respect to some recent experimental results. Stability<br>of (SAW) or (CSW) and ion reflection from them has been found to be strongly dependent on the initial<br>velocity distribution of ions. The effect of both the ion and the electron temperature on the generation<br>and evolution of solitary acoustic waves have been discussed.
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