By using the worldline instanton method we investigate the electron-positron pair production rate from a vacuum in the presence of a time-dependent field with general elliptic polarization.It is found that as field po...By using the worldline instanton method we investigate the electron-positron pair production rate from a vacuum in the presence of a time-dependent field with general elliptic polarization.It is found that as field polarization changes from a linear to a circular one,the pair production rate would change to some extent.When field strength is weak while frequency is high,the pair production rate changes significantly with polarization.However,when field strength is strong while frequency is low,the pair production rate from a vacuum is insensitive to field polarization and the results of the pair production rate are the same as those in a constant field.Our results are compared with previous work and the implications of our study are briefly discussed.展开更多
Electron acceleration in plasma driven by circular polarized ultraintense laser with asymmetric pulse axe investigated analytically and numerically in terms of oscillation-center Hamiltonian formalism. Studies include...Electron acceleration in plasma driven by circular polarized ultraintense laser with asymmetric pulse axe investigated analytically and numerically in terms of oscillation-center Hamiltonian formalism. Studies include wakefield acceleration, which dominates in blow-out or bubble regime and snow-plow acceleration which dominates in supra-bubble regime. By a comparison with each other it is found that snow-plow acceleration has lower acceleration capability. In wakefield acceleration, there exists an obvious optimum pulse asymmetry or/and pulse lengths that leads to the high net energy gain while in snow-plow acceleration it is insensitive to the pulse lengths. Power and linear scaling laws for wakefield and snow-plow acceleration respetively are observed from the net energy gain depending on laser field amplitude. Moreover, there exists also an upper and lower limit on plasma density for an effective acceleration in both of regimes.展开更多
Electron-positron pair production in a strong laser field enhanced by an assisted high frequency weak field is investigated by solving the quantum Vlasov equation.The average and residual pair number densities are obt...Electron-positron pair production in a strong laser field enhanced by an assisted high frequency weak field is investigated by solving the quantum Vlasov equation.The average and residual pair number densities are obtained for sinusoid electric field and it is found that the high frequency assisted weak field will enhance pair production significantly.There exists an optimal frequency of assisted field that makes the pair production number density get a maximum one,which is a few orders of higher than that without assisted field.We also discuss the other possible assisted fields.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 10834008,10965006,11175023 and 11165014the Fundamental Research Funds for the Central Universities(FRFCU).
文摘By using the worldline instanton method we investigate the electron-positron pair production rate from a vacuum in the presence of a time-dependent field with general elliptic polarization.It is found that as field polarization changes from a linear to a circular one,the pair production rate would change to some extent.When field strength is weak while frequency is high,the pair production rate changes significantly with polarization.However,when field strength is strong while frequency is low,the pair production rate from a vacuum is insensitive to field polarization and the results of the pair production rate are the same as those in a constant field.Our results are compared with previous work and the implications of our study are briefly discussed.
基金Supported by the National Natural Science Foundation of China(NSFC)under Grant Nos.10875015 and 10834008
文摘Electron acceleration in plasma driven by circular polarized ultraintense laser with asymmetric pulse axe investigated analytically and numerically in terms of oscillation-center Hamiltonian formalism. Studies include wakefield acceleration, which dominates in blow-out or bubble regime and snow-plow acceleration which dominates in supra-bubble regime. By a comparison with each other it is found that snow-plow acceleration has lower acceleration capability. In wakefield acceleration, there exists an obvious optimum pulse asymmetry or/and pulse lengths that leads to the high net energy gain while in snow-plow acceleration it is insensitive to the pulse lengths. Power and linear scaling laws for wakefield and snow-plow acceleration respetively are observed from the net energy gain depending on laser field amplitude. Moreover, there exists also an upper and lower limit on plasma density for an effective acceleration in both of regimes.
基金Supported by the National Natural Science Foundation of China (NNSFC) under Grant Nos. 11175023,11165014partially by theFundamental Research Funds for the Central Universities (FRFCU)
文摘Electron-positron pair production in a strong laser field enhanced by an assisted high frequency weak field is investigated by solving the quantum Vlasov equation.The average and residual pair number densities are obtained for sinusoid electric field and it is found that the high frequency assisted weak field will enhance pair production significantly.There exists an optimal frequency of assisted field that makes the pair production number density get a maximum one,which is a few orders of higher than that without assisted field.We also discuss the other possible assisted fields.
