Dynamically assisted tunneling in the impulse regime

We study the enhancement of tunneling through a potential barrier $V(x)$ by time-dependent electric field with special emphasis on pulse-shaped vector potentials such as $A_x(t)=A_0/\cosh^2(\omega t)$. In addition to known effects pre-acceleration and deformation already present in adiabatic regime, well energy mixing analogy Franz-Keldysh effect non-adiabatic (impulse) pulse $A_x(t)$ can enhance ``pushing'' part wave-function out rear end barrier. Besides natural applications condensed matter atomic physics, these findings could be relevant for nuclear fusion, where pulses $\omega=1~\rm keV$ peak strengths $10^{16}~\rm V/m$ might rates significantly.