tailieunhanh - Laser Pulse Phenomena and Applications Part 2

Tham khảo tài liệu 'laser pulse phenomena and applications part 2', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Impulsar New Application for High Power High Repetition Rate Pulse-Periodic Lasers 21 Fig. 2. Oscillograms of the laser pulse 1 and radiation pulse transmitted through the OPD 2 for f 50 kHz. attachment was mounted on the chamber end. Laser radiation was directed to the chamber through a lens with a focal distance of 17 cm. The argon jet was formed during flowing from a high-pressure chamber through a hole of diameter 3 - 4 mm. The jet velocity V was controlled by the pressure of argon which was delivered to the chamber through a flexible hose. The force produced by the jet and shock waves was imparted with the help of a thin of diameter mm molybdenum wire to a weight standing on a strain-gauge balance accurate to g . The wire length was 12 cm and the block diameter was 1 cm. The sequence of operations in each experiment was as follows. A weight fixed on a wire was placed on a balance. The model was slightly deviated from the equilibrium position in the block direction which is necessary for producing the initial tension of the wire 1 g . The reading Fm of the balance was fixed then the jet was switched and the reading of the balance decreased to F1. This is explained by the fact that the rapid jet produces a reduced pressure ejection effect in the reflector. After the OPD switching the reading of the balance became F2. The propulsion Fr produced by the OPD is equal to F1 - F2. The pressure of shock waves was measured with a pressure gauge whose output signal was stored in a PC with a step of 1 ps. The linearity band of the pressure gauge was 100 kHz. The gauge was located at a distance of 5 cm from the jet axis see Figure 1 and was switched on after the OPD ignition t 0 . The pressure was detected for 100 ms. Let us estimate the possibility of shock-wave merging in the experiment and the expected values of Fr and Jr. The merging efficiency depends on the parameters a Rd C0 and M0 V C0 M0 1 where Co is the sound speed in gas. If the distance from the OPD .