title: Characteristics of betatron radiation from direct-laser-accelerated electrons.
abstract: Betatron radiation from direct-laser-accelerated electrons is characterized analytically and numerically. It is shown here that the electron dynamics is strongly dependent on a self-similar parameter S(≡n_{e}/n_{c}a_{0}). Both the electron transverse momentum and energy are proportional to the normalized amplitude of laser field (a_{0}) for a fixed value of S. As a result, the total number of radiated photons scales as a_{0}^{2}/sqrt[S] and the energy conversion efficiency of photons from the accelerated electrons scales as a_{0}^{3}/S. The particle-in-cell simulations agree well with the analytical scalings. It is suggested that a tunable high-energy and high-flux radiation source can be achieved by exploiting this regime.
authors.affiliation: HEDPS, Center for Applied Physics and Technology and School of Physics, Peking University, Beijing 100871, People's Republic of China.|Central Laser Facility, STFC Rutherford-Appleton Laboratory, Didcot, OX11 0QX, United Kingdom.
authors.forename: T W
authors.initials: TW
authors.lastname: Huang
authors.affiliation: Central Laser Facility, STFC Rutherford-Appleton Laboratory, Didcot, OX11 0QX, United Kingdom.
authors.forename: A P L
authors.initials: AP
authors.lastname: Robinson
authors.affiliation: HEDPS, Center for Applied Physics and Technology and School of Physics, Peking University, Beijing 100871, People's Republic of China.|Institute of Applied Physics and Computational Mathematics, Beijing 100094, People's Republic of China.|College of Electronic Science and Technology, Shenzhen University, Shenzhen 518060, People's Republic of China.
authors.forename: C T
authors.initials: CT
authors.lastname: Zhou
authors.affiliation: HEDPS, Center for Applied Physics and Technology and School of Physics, Peking University, Beijing 100871, People's Republic of China.
authors.forename: B
authors.initials: B
authors.lastname: Qiao
authors.affiliation: HEDPS, Center for Applied Physics and Technology and School of Physics, Peking University, Beijing 100871, People's Republic of China.|Institute of Applied Physics and Computational Mathematics, Beijing 100094, People's Republic of China.
authors.forename: B
authors.initials: B
authors.lastname: Liu
authors.affiliation: College of Electronic Science and Technology, Shenzhen University, Shenzhen 518060, People's Republic of China.
authors.forename: S C
authors.initials: SC
authors.lastname: Ruan
authors.affiliation: HEDPS, Center for Applied Physics and Technology and School of Physics, Peking University, Beijing 100871, People's Republic of China.|Institute of Applied Physics and Computational Mathematics, Beijing 100094, People's Republic of China.
authors.forename: X T
authors.initials: XT
authors.lastname: He
authors.affiliation: Central Laser Facility, STFC Rutherford-Appleton Laboratory, Didcot, OX11 0QX, United Kingdom.|Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford, OX1 3PU, United Kingdom.
authors.forename: P A
authors.initials: PA
authors.lastname: Norreys