Detection of kinetic cooling in the atmosphere

Opto-acoustic phenomena accompanying the propagation of high-power pulsed laser radiation in the atmosphere

“…4. The setup comprised a high-power pulsed CO 2 laser (1) (λ= 10.6 µm, τ L = 1 µs, and E max = 2 kJ) described in detail in [1], bolometers (6 and 7), a set of standard sensors (8) for measuring the meteorological parameters near the laser beam propagation path (the air temperature T, the relative air humidity u, the meteorological visibility range S m , and the average wind velocity component V in the direction orthogonal to that of laser beam propagation), MK-221 half-inch omnidirectional microphones with MV-201 preamplifiers (9 and 10), PSI 00017 precise impulse sound level meters (11 and 12), ATP-10 analog-to-digital converters (ADCs) (13 and 14), S1-65 oscillographs (15 and 17), Olimp magnetic recorders (16 and 18), a K-16 CRATE-controller (19), and a computer (20). A Cassegrain telescopic system with a large parabolic mirror 50 cm in diameter (5) and a small hyperbolic mirror 12 cm in diameter (4) was used to focus laser radiation.…”

“…Table 1 it can be seen that the effect of self-focusing becomes more pronounced and may reach four minutes of arc as the HPLR energy increases. The reasons for this effect at low relative air humidity were analyzed in [20]. The results of thermoacoustic measurements of the absorption coefficient α ac for a series from 6 laser shots are presented in Table 2.…”