The proposition that nanosecond pulsed laser annealing of implanted silicon is accomplished by electron plasma interactions (below 1700 K) has been tested by comparing the threshold energy densities required for epitaxial regrowth, using intense pulsed beams of B+and Ba+ions. Thresholds for 250‐ns pulsed B+(210 keV) (90% electronic energy deposition in Si) and Ba+(285 keV) (44% electronic, 56% collisional) are identical, indicating that the mode of initial energy coupling to the solid is not important. The results agree with quantitative predictions for a normal thermal melting process.