Gamma-ray Radiation From Plasma Bubble Hosing

The CEP-dominated few cycle strong ( \begin{figure}[htbp] \centerline{\includegraphics[width=0.40in,height=0.17in]{100720171.eps}} \label{fig1} \end{figure} ) laser pulse could oscillate in a underdense plasma with a period [1], \begin{figure}[htbp] \centerline{\includegraphics[width=1.03in,height=0.19in]{100720172.eps}} \label{fig2} \end{figure} , where \begin{figure}[htbp] \centerline{\includegraphics[width=0.14in,height=0.17in]{100720173.eps}} \label{fig3} \end{figure} is the laser wavelength, \begin{figure}[htbp] \centerline{\includegraphics[width=0.14in,height=0.17in]{100720174.eps}} \label{fig4} \end{figure} is the laser critical density and \begin{figure}[htbp] \centerline{\includegraphics[width=0.15in,height=0.18in]{100720175.eps}} \label{fig5} \end{figure} is the initial plasma density. This oscillation further leads to the hosing-like oscillation of the formed plasma bubble [2] which, in turn, gives a very strong oscillation strength for the electrons trapped inside. With numbers of self-trapped electrons, this scheme is capable server as a strong and bright gamma-ray source. A stretched plasma bubble is achieved by firstly injecting a symmetric, moderately long ( \begin{figure}[htbp] \centerline{\includegraphics[width=0.24in,height=0.18in]{100720176.eps}} \label{fig6} \end{figure} ) and strong ( \begin{figure}[htbp] \centerline{\includegraphics[width=0.40in,height=0.17in]{100720177.eps}} \label{fig7} \end{figure} ) laser in to an underdense plasma. Then, many electrons can be self-trapped along with the bubble breaking due to the nonlinear plasma wave. The head erosion produces the few cycle pulse which enables the oscillation. \textbf{References:} [1] A. A. Silaev et al., Residual-Current Excitation in Plasmas Produced by Few-Cycle Laser Pulses, PhysRevLett.102.115005 (2009); [2] M. C. Kaluza et al., Observation of a Long-Wavelength Hosing Modulation of a High-Intensity Laser Pulse in Underdense Plasma, Phys. Rev. Lett.~\textbf{105}, 095003 (2010).