R. Knobloch
Technische Universität Darmstadt
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Publication
Featured researches published by R. Knobloch.
Laser and Particle Beams | 2006
Stefan Neff; R. Knobloch; D. H. H. Hoffmann; A. Tauschwitz; S.S. Yu
The transport of high-current heavy-ion beams in plasma channels is a promising option for the final transport in a heavy-ion fusion reactor, since it simplifies the construction of the reactor chamber significantly. Our experiments at the Gesellschaft fur Schwerionenforschung demonstrate the creation of 1 m long stable plasma channels and the transport of heavy-ion beams. The article outlines the experimental setup used at GSI and reports the results of beam transport measurements using these long channels. The experiments demonstrate good beam transport properties of the channel, indicating that channel transport is a viable alternative to neutralized-ballistic transport.
Laser and Particle Beams | 2002
D. Penache; Christoph Niemann; A. Tauschwitz; R. Knobloch; Stefan Neff; R. Birkner; M. GEIßEL; D. H. H. Hoffmann; R. Presura; C. Penache; Markus Roth; H. Wahl
The aim of the presented experiments is to study the transport of a heavy ion beam in a high-current plasma channel. The discharge is initiated in NH 3 gas at pressures between 2 and 20 mbar by a line-tuned CO 2 laser. A stable discharge over the entire electrode gap (0.5 m) was achieved for currents up to 60 kA. Concerning the ion beam transport, the magnetic field distribution inside the plasma channel has to be known. The ion-optical properties of the plasma channel have been investigated using different species of heavy ions (C, Ni, Au, U with 11.4 MeV/u during six runs at the Gesellschaft fur Schwerionenforschungs-UNILAC linear accelerator. The high magnetic field allowed the accomplishment of one complete betatron oscillation along the discharge channel. The results obtained up to now are very promising and suggest that, by scaling the discharge gap to longer distances, the bearn transport over several meters is possible with negligible losses.
Laser and Particle Beams | 2003
Christoph Niemann; D. Penache; A. Tauschwitz; Frank B. Rosmej; Stefan Neff; R. Birkner; C. Constantin; R. Knobloch; R. Presura; S.S. Yu; W. M. Sharp; D.M. Ponce; D. H. H. Hoffmann
The final beam transport in the reactor chamber for heavy ion fusion in preformed plasma channels offers many attractive advantages compared to other transport modes. In the past few years, experiments at the Gesellschaft fuer Schwerionenforschung (GSI) accelerator facility have addressed the creation and investigation of discharge plasmas, designed for the transport of intense ion beams. Stable, self-standing channels of 50 cm length with currents up to 55 kA were initiated in low-pressure ammonia gas by a CO{sub 2}-laser pulse along the channel axis before the discharge is triggered. The channels were characterized by several plasma diagnostics including interferometry and spectroscopy. We also present first experiments on laser-guided intersecting discharges.
Laser and Particle Beams | 2002
A. Tauschwitz; R. Birkner; R. Knobloch; Stefan Neff; C. Niemann; D. Penache; R. Presura; David Ponce; S.S. Yu
Discharge plasma channels have been investigated in recent years at Gesellschaft fur Schwerionenforschung-Darmstadt (GSI) and at the Lawrence Berkeley National Laboratory in Berkeley, California, in a number of experiments. A short of the experimental work at Berkeley and GSI is given. Different initiation mechanisms for gas discharges of up to 60 kA were studied and compared. In the Berkeley experiments, laser ionization of organic vapors in a buffer gas was used to initiate and direct the discharge while at GSI, laser gas heating and ion-beam-induced gas ionization were tested as initiation mechanisms. These three initiation techniques are compared and the stability of the resulting discharge channels is discussed. A discharge current of 50 kA, a channel diameter well below 1 cm, a pointing stability better than 200 μm, and MHD stability of more than 10 μs have been demonstrated simultaneously in the recent experiments. These parameters are sufficient or close to the requirements of a reactor application depending on the details of the target design. The experimental results show that transport channels work with sufficient stability, reproducibility, and ion optical properties for a wide pressure range of discharge gases and pressures.
international conference on plasma science | 2001
D. Penache; C. Niemann; A. Tauschwitz; R. Presura; R. Knobloch; Stefan Neff; Matthias Geissel; D. H. H. Hoffmann; C. Penache; Markus Roth; H. Wahl
Charged particle beam transport in plasma channels is a well-established technique for electron and proton beams in the 1 MeV particle energy range. Experiments with heavy ion beams were started at the GSI-UNILAC accelerator facility to explore the applicability of this transport mode to heavy ion beam driven inertial confinement fusion. These experiments investigate the ion optics of a laser-initiated discharges. With the help of a TEA-CO/sub 2/ laser a discharge is initiated in low pressure (5 to 20 mbar) ammonia gas. A capacitor bank (1.33-8 /spl mu/F), charged up to 20 kV, is then triggered and a straight plasma channel is produced along the laser path. The current can be increase up to 45 kA. Fast shutter photography was used to study the stability of the channel. Magnetic field measurements were performed with dB/dt loops. The influence of the magnetic probe on the discharge was checked using an interferometer set-up. A 2.2 GeV gold ion beam was used to probe the ion optical properties of the channel.
international conference on high power particle beams | 2004
A. Tauschwitz; R. Knobloch; Stephan Neff; C. Niemann; D. Penache; R. Presura; S.S. Yu
Archive | 2003
V. Orsic Muthig; V. Arsov; A. A. Golubev; Dieter H. H. Hoffmann; R. Knobloch; Y. Maron; Stefan Neff; J. Pozimski; U. Ratzinger; H. Riege; I. Roudskoy; Marius Schollmeier; F. Schrader; A. Tauschwitz
Archive | 2002
Christoph Niemann; A. Tauschwitz; D. Penache; Stephan Neff; R. Birkner; J. Jacoby; C. G. Constantin; Frank B. Rosmej; R. Knobloch; R. Presura; Dieter H. H. Hoffmann
Archive | 2001
D. Penache; C. Niemann; A. Tauschwitz; R. Presura; M. Geissel; C. Penache; R. Knobloch; Markus Roth; D. H. H. Hoffmann
Archive | 2001
Christoph Niemann; D. Penache; Frank B. Rosmej; A. Tauschwitz; R. Knobloch; Stephan Neff; R. Presura; R. W. Lee; D. H. H. Hoffmann