2. Shock wave propagation across the column of dusted glow discharge in different gases. A.S.Baryshnikov, I.V.Basargin, M.V.Chistyakova Ioffe Physico-Technical Institute Russia

3. PROBLEM Reducing a drag of air vehicles (due to destabilization and destruction of bow shock wave ), Moreover, Temperature and Heat Flux to surface are dropping!!! Controlling a flight of them, Without great energy deposition TMB 2010 2

4. EFFECT OF SHOCK WAVE INSTABILITY DUE TO ENDOTHEMIC REACTION EARLIER: well known instability due to exothermic reaction: detonation combustion. Gas Temperature increases! NOW: Dissociation, Ionization, Excitation of inner degrees of energy. Gas Temperature drops! TMB 2010 3

5. Problem When velocity of body riches the amount at which Chemical dissociation (not exothermic reaction) takes the place Just a disturbances on bow shock wave are arising. The flow behind body becomes disturbed in such manner as for turbulent flow. It’s important that such ”turbulence” is outside the wake flow region 1. 1. Flow of the chemically reacting stable polyatomic gases (CF 2 Cl 2 ), TMB 2010 4

6. Fig.1. Instability of bow shock wave in front of segmental body. Flow Mach number: М 0 =3,9; Gas: CF 2 Cl 2. Pressure in flow: Р 0 =3,8·10 4 Pа. Wake turbulence Single vortex Disturbance on bow shock wave М 0 =3,9 5 TMB 2010

7. Fig.2. Instability of bow shock wave in front of segmental body. Flow Mach number: М 0 =6,1; Gas: CF 2 Cl 2. Pressure in flow: Р 0 =4,3·10 4 Pа. М0=6,1М0=6,1 6 TMB 2010

8. Could! - for Air for high Mach number (2-5) ( Mach number defined to the speed of sound of the uncharged heavy particles) 2. Plasma is active medium! Could energy release to translation freedom degrees? TMB 2010 7

9. Behind fast shock wave pressure growth is proportional to  +1 (  –ratio of specific thermo capacities which in plasma is close to 1) Temperature grows much less because its growth is proportional to  -1. Electron concentration arises with temperature much faster but it drops with the pressure growth. 16.05.20158 TMB 2010

10. in according the Huguenot laws: Derivative will take the form: Equilibrium concentration of binary reaction: equilibrium constant : 16.05.20159 α TMB 2010

11. If for any Mach number   will be < than calculation curve, electron concentration will be reducing with rising of M which could correspond to recombination behind shock wave or to the flash of radiation  power index of temperature of preexponential factor in equilibrium constant 3 Mach number Region of instability Cp/Cv in plasma 16.05.201510 TMB 2010

12. Here is a stationary plasma of glow discharge. Experiments was made in the installation of electromagnetic shock tube for low transonic Mach number in plasma (hot region) (Mach number is defined to the speed of sound of the slight disturbances of the density of the uncharged heavy particles in hot plasma region) 3. Low speed plasma flow TMB 2010 11

13. Installation 1- camera; 2- electromagnetic shock tube (EMST), 3- central electrode of EMST; 4- flanges from organic glass, 5- the anode, 6- cathode; 7- receiver; 8 - rod; 9- piezoelectric pickup; 10- quartz rod; 11- gate of evacuation; 12- pump; 13- gate of gas inlet; 14- manometers. Experimental camera Electromagnetic shock tube piezoelectric pickup PUMP anode TMB 201012

14. Regimes Maximum of shock wave speed = 2 km/s The gas pressure in camera was 4·10 3 Pa (36 Torr) In experiments we have a time distribution of signal from piezo pickup oriented towards the shock wave (It corresponds to pressure distribution behind the shock wave ) Electrical current in discharge = 1 A up to 2.5A Voltage of discharge = 1 kV up to 10 kV TMB 2010 13

15. Usual electron temperature distribution across the positive column of glow discharge 10 12 1/cm 3 Electron temperature has the same profile – plate – 1 eV TMB 2010 14

16. Usual gas temperature distribution across the positive column of 1200 K TMB 201015

17. Signal from piezo pickup without the plasma in hot air (usual triangular form) TMB 201016

18. Signal from piezo pickup in the plasma (two wave form) TMB 2010 17

19. Low dustiness - preliminary results. Dust concentration is about 20 mg per cubic meter, that is comparable with natural concentration TMB 201018

20. Weak influence of dustiness for the small concentration (in ten times less) of dust ( 20mg in m 3 ; emission of laser as absorbed by 4% ), 2- maximum dustiness (solid gradient line), 1- dustiness is two times lower (dashed line), 0 - without the dust (solid line). in the center of discharge column, the initial velocity of shock wave Is the same 1.6 km/s Air N2 TMB 2010 19

21. High dustiness - refined results Dust concentration is about 200 mg per cubic meter Refined: with increased measurement precision by reducingof time discretness at signal recording to order from 200 ns to 20 ns. It enables to average number experiments at each registration point (In this study there was an averaging of 10 experiments). TMB 201020

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25. 1)For carbon dust: Weak influence of dustiness for the small concentration of dust ( 20mg per m 3 ; ), as for Air and for N 2 and Ar 2) BUT! THERE IS INFLUENCE for great concentration( in ten time greater)! 2.1) No influence for Air without plasma 2.2) No appreciable influence in Air plasma 2.3) Great influence for Argon plasma Summary TMB 201024

26. Further Investigation: A) Strange strong dust dependence on the type of gas B) Dust dependence on the kind of dust C) Dust dependence in course of time after disconnection of discharge TMB 2010 25

27. Some part of this work was made under the financial support of Russian Foundation for Basic Research project N 06-08-00663-а TMB 201026

28. Thank you very much! TMB 201027