Laser Lighting Protection
Creation of the Laser Lighting Protection System
Tech Area / Field
- PHY-OPL/Optics and Lasers/Physics
8 Project completed
Senior Project Manager
Malakhov Yu I
Institute of General Physics named after A.M. Prokhorov RAS, Russia, Moscow
- Tomsk Polytechnical University / Scientific Research Institute of High Voltage, Russia, Tomsk reg., Tomsk\nMoscow Power Engineering Institute, Russia, Moscow\nIVTAN (High Temperatures), Russia, Moscow\nVNIITF, Russia, Chelyabinsk reg., Snezhinsk
- Deutsches Zentrum für Luft- und Raumfahrt e.V. / Institut für Technische Physik, Germany, Stuttgart\nAérospatiale/Centre Commun de Recherches LOUIS BLERIOT, France, Suresnes\nCEA / CEA / DAM / DMSE, France, Bruyères le Châtel
Project summaryThe final goal of the investigations is to create a laser system of lightning protection (LLP). It is based on the use of long laser spark as active controlled lightning rod. The LLP has some advantages in comparison with traditional methods that allows to create highly reliable and efficient lightning protection of unique super-expensive industrial objects (atomic power plants, petrochemistry complexes, rocket launches, etc.). The result of the Project accomplishment will be the creation of experimental base elements of LLP - laser device and optical system for long spark formation with parameters, which meet the efficiency criteria of lightning catching.
To reach the declared goals it is necessary to perform the complex of fundamental and applied investigations. The study of physics of laser-directed discharges (LDD) as the analogue of natural lightning is the basis of fundamental investigations of the Project. The goals of these investigations are:
- study of the leader propagation mechanism;
- study of the mechanism of return strike formation and channel dynamics on times і 1 ms;
- study of the mechanism of arrow-shaped leader propagation in the air plasma cooling down after the breakdown by laser spark,
- study of the possibility of beaded lightning obtaining in the experiment on the stage of LDD channel cooling down.
The prerequisite for successful performance of this work is the accumulated experience of laboratory LDD investigations (with the length in the range from tens centimeters to 1-2 m) . However, the LDD of meter elongation is not enough for understanding physical phenomena, connected with the natural lightning propagation and their analogous. First of all it is connected with the fact, that the formation zone of lightning leader channel exceeds tens of meters.
At the Project, to create the laser spark with the length 20-25m we suggest to use CO2-laser with 2-3 kJ of radiation energy in a pulse (up to 70% of laser pulse energy' yields for the time Ј 200 ns), radiation pergence of 10-3-10-4 rad, and long-focus optical focusing system. The discharge propagating along the laser spark track is created by the source based on the pulsed voltages generator (GPV) or GPV system with amplitude Ј 2MV, rise front ~ 0.1-1 ms, pulse duration Ј 1ms. Investigation results are confirmed on the installation with the use of CO2-laser with 5kJ of radiation energy in a pulse and 3MV of output voltage.
The advantages of the considered method of studying of long air gap breakdown physics in comparison with the study of ordinary spark  mainly consist in facilitating discharge diagnostics and results interpretation connected with predetermination of breakdown track. This allows hoping additional experimental information important for understanding of physical nature of the phenomenon to be obtained. The latter is necessary for working out of requirements to device parameters needed for effective lightning catching.
Besides, we suppose to perform the laboratory investigations of linear lightning initiation possibility due to the remote impact of a long laser spark on a thunderstorm cloud. The latter will be simulated by the generator of charged water aerosols. The execution of this block of investigations could contribute to study linear lightning initiation physics, and also gives the possibility of LLP efficiency investigation by scaling of natural phenomenon in laboratory.
Results obtained during the execution of fundamental investigations will serve as a basis for solution of applied tasks, namely:
1. Determination of the laser radiation and focusing system parameters for laser spark generation, which satisfies the requirements of lightning catching efficiency criteria Experimental confirmation of catching efficiency.
Choice of optimum scheme of the LLP idea realization. The thunderstorm cloud is simulated by artificial cloud of charged water aerosols. Lightning discharge is initiated by means of laser spark. LLP system is simulated by another laser spark directed at the grounded metal lightning rod. Having varied the system configuration (start place of lightning discharge, ratio of the altitude of the charged water aerosols cloud and laser spark length - analogue LLP, etc.) it is possible to estimate the lightning protection efficiency.
Further more, it is supposed to consider the following possible use of LLP for solution of applied purposes concerning the demonstration of the method efficiency by arrangement and execution of relevant experiments.
1. Remote influence on the aerosol (including radioactive) deposition rate in the air due to coagulation (enlargement) of particles in shock wave  formed by LLP accompanied by simultaneous effect on the dangerous gas products caused by plasma-chemical reactions in corona discharge and disintegrated plasma of discharge channel.
2. Remote influence on thunderstorm cloud by laser spark in order to initiate the precipitation fall-out (hail, rain) due to water aerosol coagulation in the shock wave generated by lightning discharge. The possibilities of such method will be investigated with the use of artificial cloud of charged water aerosols.
The results of the applied investigations block fulfillment will serve as the basis for creation of experimental base LLP elements - laser installation and optical system for forming long laser sparks with parameters, which meet the requirements of lightning catching efficiency criteria. Moreover, data about LLP application efficiency for the purposes of remote influence on the aerosols deposition rate in the air will be obtained.
The project fulfillment is planned in collaboration with foreign partners (SILAS, France, White Sands, USA, CRIEPI, Japan). Regular current project problems data exchange, in particular, received results discussions, joint seminars are supposed. All the amount of the required scientific and technological data obtained during project execution will be available to the foreign partners.
The cooperation of RSA scientists, having great experience in conduction of close researches and scientists, busy with the development of nuclear weapon, having experience in organization of large-scale physical experiment, and also great possibilities of all the participating institutions experimental basis will favor the solution of declared tasks, particularly VNIIEF.
The project realization will give the possibility to VNIIEF workers to turn their efforts to the solution of civil tasks and use the scientific and technical potential of the institute in peaceful purposes. The results will be published in books and magazines, accessible for wide circle of world scientific community, reported on international conferences, which will favor the integration of VNIIEF scientists to the world science community.
1. Vasilyak L.M., Kostuchenko S.V., Kudryavtsev N.N., Filugin I.V. High-speed waves of ionization at the electric breakdown // UFN, 1994, v.64. No.3. P.263-285.
2. Gorin B.N., Shkilev A.V., development of the electric discharge in long gaps rod plane at the negative voltage // Electricity. 1976. No.2. P.31-39.
3. BelovN.N., DavydovK.A., Datskevich N.P., et al. The increase of the speed of water fogs particles deposition under the acoustic influence of radiation pulse of CO2-laser. // Letters to ZhETPh. 1983. V.37. No.3 P.139-141.