Yuri A. Rezunkov

Model Test of the Aerospace Laser Propulsion Engine

One of the main results of the experimental and theoretical investigations made under the ISTC Project ♯ 1801 is the original design of Aerospace Laser Propulsion Engine (ASLPE) developed. The designed characteristics of the ASLPE flight model are experimentally approved, including the test experiments with a solid propellant. The obtained momentum coupling coefficient is rather high and comparable one with respect to the coefficient obtained by other researchers. Moreover, it is experimentally demonstrated that the thrust characteristics of the ASLPE flight model does not depend on angular aberrations of the beam coming onto the beam concentrator of the model with the incident angle of 0.01 radian. The experiments also demonstrated that successful launching of the vehicle with the ASLPE under the laser characteristics is possible also if the vehicle mass will be decreased and the thermal blooming effect will be eliminated.

Phase conjugation in a high-power E-beam-sustained CO2 laser

The experimental demonstration of phase conjugation technique as applied to aberration correction in a high-power gas-flow CO2 laser is reported. A four-wave mixing in 34SF6 was used to obtain high efficient phase conjugation of repetition rate electron- beam-sustained CO2 laser radiation. For the first time, the nearly diffraction-limited performance of the double-pass CO2 amplifier with the phase-conjugate mirror for the output energy of about 1.2 KJ and average power of 40 KW is demonstrated.

Feasible configurations of a repetitively pulsed TEA CO2 laser with small angular divergence and 1- kJ pulse energy

The results are presented of expert evaluations aimed at developing the optimal concept of creation of a compact TEA CO2 laser with a self-sustained discharge capable of generating the repetitive bursts of ten radiation pulses with 1 kJ-energy in each and the pulse repetition rate of 30 Hz. Particular emphasis is placed on the problems of achieving as small angular divergence and beam wandering as possible.

Self-phase conjugation of middle-infrared radiation by four-wave mixing in active medium of CO2-laser with feedback loop

The ring cavity oscillation at the four-wave mixing in the carbon-dioxide-laser medium with feedback loop was studied. The cavity output energy about 5 J at the master oscillator energy of 0.5 J was observed, the phase conjugation fidelity ranged from 0.3 to 0.8.

Laser Beam Control System To Compensate The Turbulent Distortions Of Laser Beam At Introducing A Lead Angle

The peculiarities of laser radiation delivery to a space vehicle in the concept LOTV which are concerned to the introduction of a lead angle is considered. It is shown that the use of direct phase conjugation of radiation of a laser beacon beam placed on a space vehicle does not provide a required degree compensation of the radiation phase distortions caused by the turbulent atmosphere. Two‐circuit adaptive laser system for high — power radiation delivery is offered in this case. In the system the processes of registration of the information about atmospheric distortions and formation of radiation are functionally partitioned. A key element of the system is a hologram — corrector being phase analogue of distortion occurring in the laser beam path between the system and lead point.

Contraction of laser-generated plasma channels under ambient electric fields

To define more precisely the requirements to electric- physical parameters of laser-generated plasma channel needed to trigger a lightning, the analysis of the experimental data on laser-guided long gap discharges is used. The analysis is based on the developed theoretical model of the channel interaction with thunderstorm electrical fields. Two modes of leader progression form a tip of the channel are considered. The obtained data allows determining the principal conversion conditions of the channel into a leader channel. To maintain the plasma channel conductivity during the modes, two laser pulses is supposed to be used. The suggestion was tested experimentally by the use of CO2 and Nd laser.

Simulation of laser propulsion at space conditions

In the paper, the problems of laser propulsion for space application is considered. To simulate the laser propulsion creation, the computer codes are developed. These codes allow us to simulate both gas-dynamics of the propulsion creation and processes of laser pulse interaction with propellants.

Experimental verification of a bright-speckle algorithm of compensation for turbulent wandering of a repetitively pulsed CO2 laser beam

A novel algorithm of compensation for repetitively-pulsed laser beam wandering at propagation paths, caused by the atmospheric turbulence and mirror vibrations has been proposed and verified in experiments with a TE-CO2 laser. The algorithm is based on the precise temporal control of triggering each of the TE-laser pulses at the moments when the auxiliary probe cw-laser beam modified by a modal-type adaptive optics system and having exactly the same wavefront profile, as the pulsed radiation, hits the remote object (retroreflector in the pre-set point at the path exit) by its brightest speckle.

Experimental study on phase conjugation correction of distortions imposed by telescope elements

The paper presents experimental results on large scale carbon-dioxide-laser beam direction, using the telescope with nonlinear-optical dynamic compensation for distortions. Variants, using phase conjugation mirrors on base of SF6-cell and of intracavity four-wave mixing, are discussed and compared.

Four-wave mixing of radiation in the gain medium of e-beam-sustained CO2 laser

The conventional FWM phase conjugation technique and the intracavity one have been studied experimentally in a gain medium of a pulsed e-beam sustained CO2 laser. The total reflectivity of 45% for the phase-conjugate beam energy of 0.3 J is reported. The periodic temporal modulation of the laser output and of the phase-conjugate beam intensity for intracavity FWM arrangement has been observed. Two types of density gratings in the medium (temperature and acoustic ones) are used to explain experimental results.