STUDIES ON ELECTRON BEAMS  IN FAST  TRANSIENT  PLASMAS

RESEARCH GROUP Dr. Mihai Ganciu -project coordinator     Prof. dr. Ioan Iovit Popescu      Dr. Nicolae Mandache      Prof. dr. Geavit Musa      Dipl. Phys. Magda Nistor      Dipl.Phys. Eduard Dewald      Dipl. Phys. Andrea Groza    Dipl. Phys Andrei Modoran      Dipl. Phys. Cristina Penache      Dipl. Phys. Dan Penache

A collimated electron beam propagating along  a dielectric fiber by Cruise Effect is repelled   by the metallic support of the fiber

Studies of electron beams in transient plasmas started with the discovery in a french-romanian cooperation  of the generation of a confined axial stream of electrons by application of short high voltage pulses (~100ns, 20 - 50 kV)  over a special configuration of electrodes in the presence of a continuous or pulsed secondary discharge. [M.Ganciu, G.Modreanu, A.M.Pointu, I.I.Popescu, “Generation of intense pulsed electron beams by superposition of two discharges” J.Phys.D.-Appl .Phys. 27, 1370 (1994)].This confined stream appears even when these electrodes are mounted outside of the glass discharge tub.

The axial electron beam (space charge compensated by ions) has a peak current exceeding some tens of amps and the maximum  energy of electrons in the range of applied voltage. The system is in fact a new type of pseudo-spark, with external electrodes, and opens a large field for new applications.

We observed that in low pressure transient hollow cathode discharges under proper pre-ionization conditions the pulsed electron beams are captured and guided by dielectric fibers (Cruise Effect) associated with X-ray emission. This effect was studied in order to develop filamentary X-ray sources and we are investigating the physical and chemical processes due to the interaction between electron beam and the dielectric fiber for different geometry’s, dimensions and materials of the target.

The induced of very intense nonhomogenous electric fields by Cruise Effect at dielectric surfaces could permit the investigation of some processes involving material synthesis. Some preliminary studies of physical aspects involved in material synthesis in intense nonhomogenous electric fields was provided by controlled deposition of charges on liquid and solid dielectric mixture in corona discharges.

-French-Romanian Research and Traning Network (96P0079)   "High power pulsed electron beams: characterisation, optimisation and applications" (co-ordinators Prof. A.M.Pointu and Dr. M.Ganciu)           -Laboratoire de Physique des Gas et des Plasmas, Universite Paris-Sud  (Prof. Anne Marie Pointu)           -Center of Quantum Electronics, University of Texas at Dallas (Prof. C. B. Collins)      -Laboratoire des Plasmas Denses, Univesite Pierre et Marie Curie, Paris, France (Prof. Yves Vitel)    -Laboratoire de Photophysique Moleculaire, Universite Paris-Sud, Orsay, France (Dr. Guy Guelachvili)     -Department of Organic Chemistry, Polytechnic University, Bucharest, Romania (Prof. Alexandru T.Balaban)    -Faculty of Physics, University of Bucharest, Bucharest, Romania (Prof. Iancu Iova)    -Institute of Physics of Nuclear Engineering- Horia Hulubei, Bucharest, Romania (Dr. Ion Vata)    Contracts with European Office of Aerospace Research and Development (EOARD US-Air Force)        -contract F61708-96-W0193: "Spatial and energetic characterization of X-ray emission from inverse capillary discharges"        - contract F61708-96-W0276: "Study of the coupling efficiences of advanced X-ray sources of gamma-ray laser media"        -contract F61708-96-W0299: "Characterization of intense electron beams produced in hollow cathode pulsed discharges   for X-ray generation"          Two scientific emissions on French - German  TV program ARTE  emission Archimede on 22 Sept. 1998 and 9 Mars 1999   <22 Sept. 1998>    <9 Mars 1999>

 

M.V. Udrea, A.M. Pointu, G. Modreanu, M. Ganciu, I.I. Popescu, N.B. Mandache,
"Pulsed electron beam in a long filamentary discharge
J. Phys.D: Appl. Phys.,  Rapid Communications, 30, 33 (1997)

E.Dewald, K.Frank, D.H.H. Hoffmann, R.Stark, M.Ganciu, N.B.Mandache, M.Nistor, A.M.Pointu, I.-Iovitz Popescu,
"Pulsed intense electron beams generated in a transient hollow cathode discharges: fundamentals and applications",
IEEE Trans. Plasma Sci., 25, 272 (1997)

E.Dewald, M.Ganciu, N.B.Mandache, G.Musa, M.Nistor, A.M.Pointu and I.-Iovitz Popescu, K.Frank, D.H.H.Hoffmann and R.Stark, "The role of multielectrode geometry in generation of pulsed intense electron beams in preionization controlled open ended hollow cathode transient discharges",
IEEE Trans. Plasma Sci., 25, 279 (1997)

V.I.Zoran, M.Ganciu, A.M.Pointu, C.B.Collins and I.-Iovitz Popescu
"X-ray generation in inverse capillary discharges for pumping"  Hyp. Interaction, 107, 415 (1997)

 E. Dewald, K. Frank, D. H. H. Hoffmann, M. Ganciu, N. B. Mandache, M. Nistor, A. M. Pointu and I.-Iovitz Popescu,
"Intense electron beams produced in pseudospark and PCOHC for beam-plasma interaction experiments"
Nucl. Instr. and Methods in Phys. Res. A 878,   614.(1998)
 
 M. C. Enache, B. M. Novac, I. R. Smith, P. Senior, H. R. Stewardson, C. D.Hackett, B. N. Mandache and M. Ganciu,
"Magneto-optic current monitoring in an extremely harsh electromagnetic environment",
Rom. Rep. Phys., 49, 639 (1997).

N. B. Mandache, E. Dewald, M. Ganciu, M. Nistor, A. M. Pointu I.-Iovitz Popescu,
"On the mechanism of electron acceleration in open-ended hollow cathode transient discharges",
Rom. Rep. Phys., 49,  567(1997)

 M. Ganciu, N. B. Mandache, R. Presura, V. Zambreanu,
"Phenomenological picture for the initial phase of plasma focus device operation",
Rom. Rep. Phys., 49, 146 (1997)

M.C.Penache, S.Enescu, D.Manaila, D.Penache, M.Ganciu, V.Zoran, I.Iovit Popescu, "An energy dispersive absorption method for charcterization of X-ray emission in pulsed discharges", Rom. Rep in Physics,  49, 177 (1998)

M.Ganciu, S. Udrea, M. C. Penache, I. Vata, I. Iovitz-Popescu, M.A. Ilies, M. Corcimaru, A. Papoiu, B. Serban, A. T. Balaban, “Corona discharge controlled aggregation and segregation of solid materials in liquids and associated ehd phenomena”,
Rom. J. Phys, 43, 67 (1998)

E. Dewald, M. Ganciu, N. B. Mandache, G. Musa, M. Nistor, A. M. Pointu, I.-Iovitz Popescu,
"Characterization of intense electron beams produced in preionization controlled transient hollow cathode discharges"
Rom. Rep. Phys., 49, 169 (1998)

I. Iovitz-Popescu, M. Ganciu, Maria-Cristina Penache, D. Penache, "On the Lavalette ranking law",
Rom. Rep. in Phys., 49, 3 (1998)

C.B.Collins, C.Diplasu, A.Surmeian, M. Ganciu, A.M.Pointu, G.Musa, I-Iovitz Popescu," Long and intense constricted pulsed discharge at low gas pressures",
Rom.  Rep. in Phys., 49, 163 (1998)

M.Ganciu, "Necesite fait loi", Pour la science (french edition of Scientific American), 258, 8 (1999)

E. Dewald, K. Frank,A.M. Pointu, D.H. Hoffmann, R. Stark, M. Ganciu, N.B. Mandache, M. Nistor, I.I. Popescu, "Intense pulsed electron beams produced in multigap and single gap PCHOCC", ICPIGXXIII, Toulouse (France), July 17-22, 1997

G. Modreanu, M. Ganciu, N.B. Mandache, A.M. Pointu, "Time and space resolved energy distribuio of an electron beam produced in a filamentary transient discharge", ICPIGXXIII, Toulouse (France), July 17-22, 1997

E. Dewald, K. Frank, D.H.H. Hoffmann, M. Ganciu, N.B. Mandache, M. Nistor, A.M. Pointu, I.I. Popescu, " Pseudospark and   PCHOH produced electron beams a comparative study", 12th Int. Conf. on Gas Discharges and their Applications, Greifswald (Germany) , 8th-12th september 1997

N. Mandache, M. Nistor, II. Popescu and S. Udrea, M. Ganciu, G.Modreanu and A.M. Pointu, E. Dewald, K. Frank and D.F. Hoffmann, "Intense electron beams in open ended hollow cathode transient discharges for table X-ray sources", First Int. Workshop on Induced gamma emission, IGE'97, Predeal (Romania), 16-20 August, 1997

M. Ganciu, C. B. Collins, M. C. Penache, D. Penache, V. Zoran, I.-I. Popescu "Fillamentary X-ray source by cruise effect", invited lecture at First Int. Workshop on Induced gamma emission,  IGE'97, Predeal (Romania), 16-20 August, 1997

E. Dewald, K. Frank, A.M.Pointu, D.H.H.Hoffmann, M.Schlaug, R.Stark, M.Ganciu, N.B.Mandache, M.Nistor, I.-Iovitz.Popescu “Intense pulsed electron beams for beam-plasma interaction experiments”, GSI-97-08 Report, June 1997, p.13

E. Dewald, K. Frank, D. H. H. Hoffmann, M. Ganciu , N. B. Mandache, M. Nistor, A. M. Pointu, I. I. Popescu, “Pulsed in tense electron beams produced in pseudospark and pcohc for beam-plasma interaction experiments”, 12th Int. Symposium on Heavy Ion Inertial Fusion and 8th Int. Workshop on Atomic Physics for Ion-Driven Fusion, Heidelberg, Sept. 22-27, 1997

G. Modreanu, M. Nistor, N. B. Mandache, A. M. Pointu, E. Dewald, M. Ganciu, I.-Iovitz Popescu "Time resolved energy distribution function of an electron beam produced in pseudospark-like discharges" XIV ESCAMPIG, Malahide, Dublin, Ireland, August 26-29, 1998.

M.Ganciu, A.M. Pointu, "Electron beams generated in open hollow cathode low pressure transient descharges", -invited lecture at XXIV ICPIG, Warsaw, Poland, 11-16 July 1999:

 A.Groza, M. Ganciu, Th.Ionescu Bujor, I.I.Popescu, M.Ilies, A.T.Balaban "Corona discharge interaction with a silicon oil-silicagel sphere mixture"  XXIV ICPIG, Warsaw, Poland, 11-16 July 1999:

M.Nistor, N.M.Mandache, E.Dewald, M. Ganciu, I.I.Popescu,A.M.Pointu, Y.Vitel "Electron energy spectra of an open ended pin-hollow cathode transient discharge by magnetic analysis" XXIV ICPIG, Warsaw, Poland, 11-16 July 1999.