Ion acceleration with ultra intense and ultra short laser pulses
Description
Accelerating ions/protons can be done using short laser pulse (few femto-seconds) focused on few micrometers area on solid target (carbon, aluminum, plastic...). The electromagnetic field intensity reached on target (≥1018 W.cm-2) allows us to turn the solid into a hot dense plasma. The dynamic motion of the electrons is responsible for the creation of intense static electric field at the plasma boundaries. These electric fields accelerate organic pollutants (including protons) located at the boundaries. This acceleration mechanism known as the Target Normal Sheath Acceleration (TNSA) has been the topic of the research presented in this thesis.The goal of this work has been to study the acceleration mechanism and to increase the maximal ion energy achievable. Indeed, societal application such as proton therapy requires proton energy up to few hundreds of MeV. To proceed, we have studied different target configurations allowing us to increase the laser plasma coupling and to transfer as much energy as possible to ions (target with microspheres deposit, foam target, grating). Different experiments have also dealt with generating a pre-plasma on the target surface thanks to a pre-pulse. On the application side, fluorescent material such as CdWO4 has been studied under high flux rate of protons. These high flux rates have been, up to now, beyond the conventional accelerators capabilities. (author)
Abstract (French)
Pour accelerer des ions/protons il est possible d'utiliser une impulsion laser de courte duree temporelle (quelques dizaines de femtosecondes) focalisee sur quelques micrometres sur une cible solide (aluminium, carbone, plastique...). L'intensite du champ electromagnetique atteinte sur cible (≥ 1018 W.cm-2) nous permet de former un plasma chaud et dense. La dynamique des electrons de ce plasma genere des champs electriques intenses aux interfaces plasma-vide par separation de charge. Ce champ electrique est alors responsable de l'acceleration des ions situes sur la couche superficielle des cibles ou se sont deposes des polluants organiques (dont des protons). Ce mecanisme d'acceleration connu sous le nom de Target Normal Sheath Acceleration (TNSA), a constitue l'objet des travaux exposes dans cette these. Nos efforts au cours des differentes campagnes experimentales se sont concentres sur l'augmentation de l'energie maximale des protons. En effet, les applications potentielles des particules de hautes energies requierent des energies de l'ordre de la centaine de MeV. Pour ce faire, nous avons etudie differentes configurations permettant l'augmentation du couplage entre une impulsion laser et un plasma, ceci afin de transmettre avec le meilleur rendement possible, l'energie du laser aux ions acceleres. C'est principalement en utilisant des configurations particulieres de cibles (cibles avec microspheres, reseaux, cibles en mousses) que nous avons procede. Des experiences utilisant une pre-impulsion comme controle de l'expansion du plasma ont egalement ete realisee. Du point de vue des applications et utilisations des ions acceleres, une etude des materiaux de fluorescence (CdWO4) a ete menee dont le but etait d'explorer le depot d'energie des ions dans la matiere, a des debits de flux jusqu'alors inaccessible avec les accelerateurs conventionnelsFiles
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Additional details
Additional titles
- Original title (French)
- Generation d'ions rapides par impulsions laser ultra intenses et ultra courtes
Identifiers
Publishing Information
- Imprint Pagination
- 128 p.
- Report number
- FRCEA-TH--3840
INIS
- Country of Publication
- France
- Country of Input or Organization
- France
- INIS RN
- 44048743
- Subject category
- S70: PLASMA PHYSICS AND FUSION TECHNOLOGY;
- Resource subtype / Literary indicator
- Thesis
- Descriptors DEI
- CADMIUM TUNGSTATES; ELECTROMAGNETIC FIELDS; HOT PLASMA; IONS; LASERS; MOTION; PLASMA; PROTONS
- Descriptors DEC
- BARYONS; CADMIUM COMPOUNDS; CHARGED PARTICLES; ELEMENTARY PARTICLES; FERMIONS; HADRONS; INORGANIC PHOSPHORS; NUCLEONS; OXYGEN COMPOUNDS; PHOSPHORS; PLASMA; REFRACTORY METAL COMPOUNDS; TRANSITION ELEMENT COMPOUNDS; TUNGSTATES; TUNGSTEN COMPOUNDS
Optional Information
- Notes
- 85 refs.; Available from the INIS Liaison Officer for France, see the 'INIS contacts' section of the INIS-NKM website for current contact and E-mail addresses: http://www.iaea.org/INIS/contacts/