Study of transient fields with Proton Imaging Toma Toncian Bad Breisig October 2008 GRK1203 TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AAAAAAAA

Contributors M. Amin, T. Kudyakov, A.C. Pipahl, O. Willi University of Düsseldorf, Germany M. Borghesi, C.A. Cecchetti, P.A. Wilson Queen‘s University, Belfast, UK P. Antici, P. Audebert, J. Fuchs LULI Ecole Polytechnique, France, R. Clark, M. Notley CLF, Rutherford Appleton Laboratory,UK Experiments were carried out at LULI and RAL funded by EU LASERLAB

Laser triggered micro lens shows very transient electric field behavior. Why? T. Toncian et al., Science Vol. 312, 41 (2006) Patent: O. Willi, T. Toncian, M. Borghesi, J. Fuchs Deutsche Patentanmeldung PILZ (2005) also filed in US, EU and Japan diverging proton beam proton source foil focused proton beam hollow metal cylinder Lens effective for ~15-20 ps

Outline Setup and principle of proton imaging Examples Angled setup for continuous time resolved measurements Measurements of plasma decay from the laser-triggered micro lens Beam propagation induced instability Electro thermal instability Summary and Outlook

Mesh (Proton Deflectometry) Proton target Interaction target Proton detector (stack of Radiochromic films) CPA beam Proton beam ~ µm spatial resolution: ~ ps temporal resolution: Magnification: Ll Interaction beam Set-Up Virtual point source  t ~ MAX (burst duration,  t fer,  t tof )  s ~ virtual source size Proton Imaging for detection of electric and magnetic fields in laser-plasmas

Results of ion front expansion 500 µm time 1 ps3 ps7 ps13 ps17 ps time 24 ps 38 ps 100 ps CPA interaction Proton beam Set-Up CPA 40 µm Al target L. Romagnani et al., PRL 95, (2005) Fields are transient but structure is constant

Field development from a wire

Transient electric field behavior from a laser irradiated cylinder

Continuous Time Evolution possible with angled probing geometry one dimension combines time and space can be evaluated if the fields evolution is independent from the position on the target

Plasma decay from a laser irradiated cylinder – angled probing geometry early decay late filamentation

Early decay – 2D PIC PSC

Beam Propagation Instability – 2D PIC PSC Ray tracing trough PSC fields agrees with experimental features

Late time filamentation Haines in PRL 47, 917 (1981) electro thermal instability  = 15 µm  = 20 ps e-ce-ce-ce-c e-ce-ce-ce-c e-he-he-he-h e-ce-ce-ce-c e-ce-ce-ce-c

Summary proton imaging is powerful diagnostic for the detection of transient electric and magnetic fields proton imaging time resolution was further enhanced employing a angled geometry setup applied to understand the physical processes behind the collapse of the fields of the laser triggered micro lens

Outlook: proton production at the 100 TW HHUD laser First proof of principle experiments show a very high laser contrast multi-fs simulations predicts ns-contrast > 10 10