RF/Microwave Electromagnetic Pulse Emission from Plasmas
C.-C. Cheng, E.M. Wright and J.V. Moloney
Plasma channels left in the wake of femtosecond light strings in the atmosphere can emit intense electromagnetic pulses (EMP) in the RF/Microwave region of the spectrum. These pulses are emitted long after the optical interaction that creates the plasma.
We estimate that each transient EMPs can reach electrical field strengths on the order of tens of kV per meter. A multi-TW laser pulse can create hundreds of light strings and associated plasma channels within a single pulse.
In a recent paper1, we proposed that the emission wavelength of the EMP could provide a useful experimental diagnostic of the peak plasma density created during the explosive self-focusing event that creates the light string.
1. C.-C. Cheng, E.M. Wright and J.V. Moloney, Phys. Rev. Letters, 87, 213001, (2001)