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Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Effect of laser temporal intensity skew on enhancing pair production in laser - Electron-beam collisions
AU - Bradley, L. E.
AU - Streeter, M. J.V.
AU - Murphy, C. D.
AU - Arran, C.
AU - Blackburn, T. G.
AU - Galletti, M.
AU - Mangles, S. P.D.
AU - Ridgers, C. P.
PY - 2021/9/9
Y1 - 2021/9/9
N2 - Recent high-intensity laser experiments (Cole et al 2018 Phys. Rev. X 8 011020; Poder et al 2018 Phys. Rev. X 8 031004) have shown evidence of strong radiation reaction in the quantum regime. Experimental evidence of quantum effects on radiation reaction and electron-positron pair cascades has, however, proven challenging to obtain and crucially depends on maximising the quantum parameter of the electron (defined as the ratio of the electric field it feels in its rest frame to the Schwinger field). The quantum parameter can be suppressed as the electrons lose energy by radiation reaction as they traverse the initial rise in the laser intensity. As a result the shape of the intensity temporal envelope becomes important in enhancing quantum radiation reaction effects and pair cascades. Here we show that a realistic laser pulse with a faster rise time on the leading edge, achieved by skewing the temporal envelope, results in curtailing of pair yields as the peak power is reduced. We find a reduction in pair yields by orders of magnitude in contrast to only small reductions reported previously in large-scale particle-in-cell code simulations (Hojbota et al 2018 Plasma Phys. Control. Fusion 60 064004). Maximum pairs per electron are found in colliding 1.5 GeV electrons with a laser wakefield produced envelope 7.90 × 10-2 followed by a short 50 fs Gaussian envelope, 1.90 × 10-2, while it is reduced to 8.90 × 10-5, a factor of 100, for an asymmetric envelope.
AB - Recent high-intensity laser experiments (Cole et al 2018 Phys. Rev. X 8 011020; Poder et al 2018 Phys. Rev. X 8 031004) have shown evidence of strong radiation reaction in the quantum regime. Experimental evidence of quantum effects on radiation reaction and electron-positron pair cascades has, however, proven challenging to obtain and crucially depends on maximising the quantum parameter of the electron (defined as the ratio of the electric field it feels in its rest frame to the Schwinger field). The quantum parameter can be suppressed as the electrons lose energy by radiation reaction as they traverse the initial rise in the laser intensity. As a result the shape of the intensity temporal envelope becomes important in enhancing quantum radiation reaction effects and pair cascades. Here we show that a realistic laser pulse with a faster rise time on the leading edge, achieved by skewing the temporal envelope, results in curtailing of pair yields as the peak power is reduced. We find a reduction in pair yields by orders of magnitude in contrast to only small reductions reported previously in large-scale particle-in-cell code simulations (Hojbota et al 2018 Plasma Phys. Control. Fusion 60 064004). Maximum pairs per electron are found in colliding 1.5 GeV electrons with a laser wakefield produced envelope 7.90 × 10-2 followed by a short 50 fs Gaussian envelope, 1.90 × 10-2, while it is reduced to 8.90 × 10-5, a factor of 100, for an asymmetric envelope.
KW - electron collisions
KW - pair production
KW - plasma optics
KW - quantum electrodynamics
KW - radiation reaction
KW - strong-field
U2 - 10.1088/1367-2630/ac1ed6
DO - 10.1088/1367-2630/ac1ed6
M3 - Journal article
AN - SCOPUS:85115228878
VL - 23
JO - New Journal of Physics
JF - New Journal of Physics
SN - 1367-2630
IS - 9
M1 - 095004
ER -