  We demonstrate a scheme for enhanced proton acceleration from
near-critical-density targets by splitting a laser pulse into a linearly and a
circularly polarized laser pulse. The combination of two laser pulses generates
a shock wave as well as hole boring effect at the front surface of the target.
Protons at the front get combined acceleration from the two acceleration
mechanisms. 2D-PIC simulation shows nearly two-fold enhancement in proton
energy from this mechanism for a near-critical density target. The acceleration
mechanism is also studied with different target density and thickness to
ascertain the target parameters over which the acceleration process shows
dominant behaviour.
