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Gain‐switched CO2 laser pulses of 225 J were focused onto planar carbon targets in the presence of longitudinal magnetic fields up to 105 kG. For fields above 25 kG, the mass loss and cross‐sectional area of the cylindrical blow‐off plasma varied as B−6/5. For these cases, only the 60‐nsec gain‐switched laser spike caused target damage; the 1.5‐μsec tail was absorbed by a ∼100‐eV partially confined plasma extending several cm from the target. The field dependence of the plasma cross section is consistent with an adiabatic expansion against the magnetic field. more...

An attempt was made to detect cosmic ray tracks using a pulsed TEA CO2 laser. Within 4 μsec of the passage of a cosmic ray through a pressurized cell, a laser beam of 4 J/cm2 energy density at 10.6 μ was fired. Pure argon and argon‐krypton mixtures were studied at pressures up to 12 atm. Spots of light were seen but no tracks. Laser damage to the cell windows was the limiting factor. An alternative detector using an initial high‐voltage pulse followed by a laser pulse is proposed. more...