The dynamics of the plasma ions in the wake fields of short, ultraintense laser pulses in underdense plasmas are investigated analytically and numerically. Owing to the large ion-to-electron mass ratio, the motion of plasma ions in such wake fields has often been assumed to be neglectable. It is shown that when the laser intensity exceeds 10<sup>20</sup> W/cm<sup>2</sup>, the ion motion can no longer be ignored. In this case, ion momentum peaks appear behind the laser pulse, which correspond with the ion density peaks. The laser-excited wake field appears to be effective for ion acceleration, in particular to ions with high-charge numbers. The dependence of ion acceleration on the laser intensity, pulse width, and background plasma density is discussed.
© 2006 Optical Society of America
Other Areas of Optics
Original Manuscript: June 22, 2005
Revised Manuscript: November 15, 2005
Manuscript Accepted: December 16, 2005
F. Yan, Z. M. Sheng, Q. L. Dong, J. Zhang, and W. Yu, "Ion acceleration in laser-excited plasma wake fields," J. Opt. Soc. Am. B 23, 1190-1195 (2006)