Simulating experiments for ultra-intense laser-vacuum interaction

Transcription

1 Simulating experiments for ultra-intense laser-vacuum interaction Nina Elkina LMU München, Germany March 11, 2011 Simulating experiments for ultra-intense laser-vacuum interaction March 11, / 23

2 Planned experimental setup Simulating experiments for ultra-intense laser-vacuum interaction March 11, / 23

3 Specific features of radiation at high fields Syncrotron motion F (x) = x x K 5/3dx Specific features Beaming θ < γ 1 Peaked spectrum di rad dω = 3 e 3 ( ) B ω 2π mc 2 F, ω c = 3eBγ2 ω c 2mc Intensity of radiation for laser field: I rad = 2e4 B 2 γ 2 3m 2 c 3 γ a 0 = ee mcω, E H Simulating experiments for ultra-intense laser-vacuum interaction March 11, / 23

4 Troubles with photons: New physics regimes Simulating experiments for ultra-intense laser-vacuum interaction March 11, / 23

5 Radiation reaction in classical regime non-hamiltonian dynamics (friction term Q i ) : ṗ i = H q i + Q i q i = H p i Reduction to one-particle distribution function leads to: ( { f t + p f mγ r + e E + p B } ) + Q γm f p = f Q p (1) Radiation reaction term Q via the Landau-Lifshitz equation: { Q = 2e3 3m 2 c 3 γ 1/2 D F [ ] L + e E B + 1 B Dt mc c ( B v) + 1 E( v c E) [ ( e mc 2 γ2 v E + v B c ) 2 ( E ]} v) 2 c 2 Simulating experiments for ultra-intense laser-vacuum interaction March 11, / 23

6 Classical motion Simulating experiments for ultra-intense laser-vacuum interaction March 11, / 23

7 Classical radiation reaction Simulating experiments for ultra-intense laser-vacuum interaction March 11, / 23

8 Quantum picture: Just Compare!!! Simulating experiments for ultra-intense laser-vacuum interaction March 11, / 23

9 Kinetic transport theory for the QED plasma Photon absorbtion ( f dt + p f ε r + q E + p B ) f ɛ p = Qrad + Q rad + + Q cr Photon emission Pair creation Kinetic equation for photon f γ t + k f γ ω r = Qγ + Qγ Simulating experiments for ultra-intense laser-vacuum interaction March 11, / 23

10 Kinetic transport theory for the QED plasma Photon absorbtion ( f dt + p f ε r + q E + p B ) f ɛ p = Qrad + Q rad + + Q cr Photon emission Pair creation Kinetic equation for photon f γ t + k f γ ω r = Qγ + Qγ Simulating experiments for ultra-intense laser-vacuum interaction March 11, / 23

11 Kinetic transport theory for the QED plasma Photon absorbtion ( f dt + p f ε r + q E + p B ) f ɛ p = Qrad + Q rad + + Q cr Photon emission Pair creation Kinetic equation for photon f γ t + k f γ ω r = Qγ + Qγ Simulating experiments for ultra-intense laser-vacuum interaction March 11, / 23

12 Particles in cell method (units = c = 1): Quasi-particles with adaptive weights f = i w i δ( u u i )S( r r i ) Equation of motion for quasi-particles d u dt = d r dt = u γ, ( Maxwell equations E + u B γ d r γ dt = k ω ) ± δ p m E t = B 4π J B t = E Simulating experiments for ultra-intense laser-vacuum interaction March 11, / 23

13 Semiclassical motion of quasiparticle on grid Simulating experiments for ultra-intense laser-vacuum interaction March 11, / 23

14 Outline of QED-PIC method Simulating experiments for ultra-intense laser-vacuum interaction March 11, / 23

15 Nonlinear Compton scattering in crossed-field E B ( 1 ) Photon emission e ± + n ω l e ± + γ: dw rad (ε γ ) = αm2 c 4 dε γ ε 2 Ai (ξ) dξ + e Motion is quasiclassical in external classical field Volkov states are used to calculate probabilities Ai(x) Airy function, and χ γ χ γ = e ( ε ) 2 E m 3 c 4 c + k H ( k E) 2, x ( ) 2 x + χ γ x Ai (x), Total probabilities 1 [Nikishov and Ritus, 1964] Simulating experiments for ultra-intense laser-vacuum interaction March 11, / 23

16 Collimated γ beam I = W/cm 2 I = W/cm 2 Laser pulse duration: T = 25 fs T = 25 fs Electron beam energy: ε = 800 MeV ε = 100, 800 MeV Beam radius R = 1µm R = 1 µm Laser focus radius R = 1µm R = 1 µm N e ± 20/shot None N γ 10 γ per e 1 (2) Simulating experiments for ultra-intense laser-vacuum interaction March 11, / 23

17 Simulation results Simulating experiments for ultra-intense laser-vacuum interaction March 11, / 23

18 Simulation results Simulating experiments for ultra-intense laser-vacuum interaction March 11, / 23

19 Simulation results Simulating experiments for ultra-intense laser-vacuum interaction March 11, / 23

20 Simulation results Simulating experiments for ultra-intense laser-vacuum interaction March 11, / 23

21 Simulation results Simulating experiments for ultra-intense laser-vacuum interaction March 11, / 23

22 Simulation results Simulating experiments for ultra-intense laser-vacuum interaction March 11, / 23

23 Spectra for a = 10 3, ε e = 800 MeV Simulating experiments for ultra-intense laser-vacuum interaction March 11, / 23

24 e + e pairs production at focus by γ-quanta beam a = 1000, γ γ = 1000 Simulating experiments for ultra-intense laser-vacuum interaction March 11, / 23

25 Summary New physical regime of laser-matter interaction is expected at the intensity level I = W/cm 2 due to radiation self-reaction effects and of laser-supported QED cascades. Quantum vs. Classical radiation self-reaction models comparison in the overlapping validity range shown qualitative differences in laser-plasma interaction. Using quantum model for hard photons we have esimulated γ production due to nonlinear Compton scattering. To simulate the QED effects (hard photons and pairs) we have developed a new transport PIC code + Monte-Carlo event generators. Simulating experiments for ultra-intense laser-vacuum interaction March 11, / 23