Intra-pulse transition between ion acceleration mechanisms in intense laser-foil interactions
Abstract
Multiple ion acceleration mechanisms can occur when an ultrathin foil is irradiated with an intense laser pulse, with the dominant mechanism changing over the course of the interaction. Measurement of the spatial-intensity distribution of the beam of energetic protons is used to investigate the transition from radiation pressure acceleration to transparency-driven processes. It is shown numerically that radiation pressure drives an increased expansion of the target ions within the spatial extent of the laser focal spot, which induces a radial deflection of relatively low energy sheath-accelerated protons to form an annular distribution. Through variation of the target foil thickness, the opening angle of the ring is shown to be correlated to the point in time transparency occurs during the interaction and is maximized when it occurs at the peak of the laser intensity profile. Corresponding experimental measurements of the ring size variation with target thickness exhibit the same trends and provide insight into the intra-pulse laser-plasma evolution.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jun 01, 2016
- Source ID
- 10.1063/1.4954654
Entities
People
- B. Gonzalez-izquierdo
- D. A. Maclellan
- D. C. Carroll
- D. Neely
- H. Padda
- H. W. Powell
- L. C. Stockhausen
- M. Borghesi
- M. King
- N. M. H. Butler
- P. Mckenna
- R. Capdessus
- R. J. Gray
- R. Wilson
- Rachel J Dance
- X. H. Yuan
Organizations
- Air Force Research Laboratory
- Engineering and Physical Sciences Research Council
- Queen's University Belfast
- Science and Technology Facilities Council
- Shanghai Jiao Tong University
- University of Strathclyde