  We present experimental results for the controlled mitigation of
electromagnetic pulses (EMP) produced in interactions of the 1PW high-power
30fs Ti:Sa laser VEGA-3 with matter. This study aims at the band of very high
frequencies (VHF), notably hundreds of MHz, comprising the fundamental cavity
modes of the rectangular VEGA-3 vacuum chamber. We demonstrate mode suppression
by tailoring of the laser-produced space charge distribution.
