2,145 research outputs found
High Power Gamma-Ray Flash Generation in Ultra Intense Laser-Plasma Interaction
When high-intensity laser interaction with matter enters the regime of
dominated radiation reaction, the radiation losses open the way for producing
short pulse high power gamma ray flashes. The gamma-ray pulse duration and
divergence are determined by the laser pulse amplitude and by the plasma target
density scale length. On the basis of theoretical analysis and particle-in-cell
simulations with the radiation friction force incorporated, optimal conditions
for generating a gamma-ray flash with a tailored overcritical density target
are found.Comment: 12 pages, 5 figures Accepted for publication in Physical Review
Letters (this http://prl.aps.org/
Experimental Test of a New Equality: Measuring Heat Dissipation in an Optically Driven Colloidal System
Measurement of energy dissipation in small nonequilibrium systems is
generally a difficult task. Recently, Harada and Sasa [Phys.Rev.Lett. 95,
130602(2005)] derived an equality relating the energy dissipation rate to
experimentally accessible quantities in nonequilibrium steady states described
by the Langevin equation. Here, we show the first experimental test of this new
relation in an optically driven colloidal system. We find that this equality is
validated to a fairly good extent, thus the irreversible work of a small system
is estimated from readily obtainable quantities.Comment: 4 pages, 6 figure
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