scholarly journals Study of drift compression for heavy ion beams

2002 ◽  
Vol 20 (4) ◽  
pp. 565-568 ◽  
Author(s):  
HONG QIN ◽  
RONALD C. DAVIDSON
Keyword(s):  
Space Charge ◽  
Pulse Shaping ◽  
Heavy Ion ◽  
Ion Beams ◽  
Longitudinal Dynamics ◽  
Heavy Ion Fusion

The longitudinal dynamics of drift compression and pulse shaping for a space-charge-dominated heavy ion fusion beam is studied. A nonperiodic quadrupole lattice is designed for a beam undergoing drift compression, and an adiabatically matched solution is found for the transverse envelope equations in the nonperiodic lattice.

scholarly journals Simulations of longitudinal instabilities in ion induction linear accelerators

1992 ◽  
Vol 10 (3) ◽  
pp. 511-529 ◽  
Author(s):  
Stanley Humphries
Keyword(s):  
Space Charge ◽  
Transmission Lines ◽  
Axial Velocity ◽  
Cell Model ◽  
Heavy Ion ◽  
Velocity Spread ◽  
Continuous Systems ◽  
Linear Accelerators ◽  
Simulation Code ◽  
Heavy Ion Fusion

This article describes computer simulations of a longitudinal instability that affects induction linear accelerators for high-power ion beams. The instability is driven by axial bunching of ions when they interact with acceleration gaps connected to input transmission lines. The process is similar to the longitudinal resistive wall instability in continuous systems. Although bunching instabilities do not appear in existing induction linear accelerators for electrons, they may be important for proposed ion accelerators for heavy ion fusion. The simulation code is a particle-in-cell model that describes a drifting beam crossing discrete acceleration gaps with a self-consistent calculation of axial space charge forces. In present studies with periodic boundaries, the model predicts values for quantities such as the stabilizing axial velocity spread that are in good agreement with analytic theories. The simulations describe the nonlinear growth of the instability and its saturation with increased axial emittance. They show that an initially cold beam is subject to a severe disruption that drives the emittance well above the stabilized saturation levels. The simulation results confirm that axial space charge forces do not reduce axial beam bunching. In fact, space charge effects increase the axial velocity spread required for stability. With simple resistive driving circuits, the model predicts velocity spreads that are too high for heavy ion fusion applications. Several processes currently under study may mitigate this result, including advanced pulsed power switching methods, enhanced gap capacitance, and an energy spread impressed between individual beams of a multibeam transport system.

scholarly journals Final compression beamline systems for heavy ion fusion drivers

2011 ◽  
Vol 29 (3) ◽  
pp. 279-282 ◽  
Author(s):  
Y.Y. Lau ◽  
Simon S. Yu ◽  
John J. Barnard ◽  
Peter A. Seidl
Keyword(s):  
Pulse Length ◽  
Heavy Ion ◽  
Spot Size ◽  
Ion Beams ◽  
Longitudinal Compression ◽  
Emittance Growth ◽  
Heavy Ion Fusion

AbstractWe have identified a general final compression section for HIF drivers, the section between accelerator and the target. The beams are given a head to tail velocity tilt at the beginning of the section for longitudinal compression, while going through bends that direct it to the target at specific angle. The aim is to get the beams compressed while maintaining a small centroid off-set after the bends. We used a specific example, 1 MJ driver with 500 MeV Rubidium + 1 ion beams. We studied the effect of minimizing dispersion using different bend strategies, and came up with a beamline point design with adiabatic bends. We also identified some factors that lead to emittance growth as well as the minimum pulse length and spot size on the target.

scholarly journals Preliminary design of a ≈10 MV ion accelerator for HIF research

1987 ◽  
Vol 5 (3) ◽  
pp. 457-463 ◽  
Author(s):  
T. J. Fessenden ◽  
C. M. Celata ◽  
A. Faltens ◽  
T. Henderson ◽  
D. L. Judd ◽  
...  
Keyword(s):  
Heavy Ion ◽  
Ion Beams ◽  
Preliminary Design ◽  
Lawrence Berkeley Laboratory ◽  
Ion Accelerator ◽  
Small Spot ◽  
Heavy Ion Fusion ◽  
Accelerator Design

An experiment to study the physics of merging and of focusing ion beams is under development at the Lawrence Berkeley Laboratory. In this design, parallel beams of ions (C+, Al+, or Al++) are accelerated to several MV and merged transversely. The merged beams are then further accelerated and the growth in transverse and longitudinal emittance is determined for comparison with theory. The completed apparatus will be used to study problems associated with focusing ion beams to a small spot as required for heavy ion fusion. Details of the accelerator design and considerations of the physics of combining beams are presented.

scholarly journals Particle simulation code for longitudinal dynamics of heavy ion beams

1981 ◽  
Author(s):  
A. Sternlieb ◽  
L. Smith ◽  
L.J. Laslett ◽  
J. Bisognano ◽  
I. Haber
Keyword(s):  
Heavy Ion ◽  
Ion Beams ◽  
Particle Simulation ◽  
Simulation Code ◽  
Longitudinal Dynamics

scholarly journals Longitudinal dynamics and stability in beams for heavy-ion fusion

1996 ◽  
Author(s):  
W. M. Sharp ◽  
D. A. Callahan ◽  
D. P. Grote
Keyword(s):  
Heavy Ion ◽  
Longitudinal Dynamics ◽  
Heavy Ion Fusion

scholarly journals New concept on the application of supersonic gas jets for space charge neutralized beam transport in an ICF reactor chamber

1997 ◽  
Vol 15 (2) ◽  
pp. 231-233
Author(s):  
P. Spiller ◽  
V. L. Varentsov
Keyword(s):  
Space Charge ◽  
Plasma Channel ◽  
Ballistic Transport ◽  
Supersonic Jet ◽  
Heavy Ion ◽  
Beam Transport ◽  
Channel Stability ◽  
High Current Discharge ◽  
Gas Expansion ◽  
Heavy Ion Fusion

One of the most crucial problems of a heavy ion fusion (HIF) driver is the transport of the beam from the final focusing system to the fusion target. The conventional focusing scheme is based on ballistic transport, assuming that all space charge effects can be kept sufficiently small. To achieve a space charge neutralized beam transport, other more sophisticated schemes like beam transport in a plasma channel have been suggested. Inspired by the results of the first experiments on the generation of adequate discharge-driven plasmas, we suggest applying a pulsed supersonic gas jet for the high-current discharge channel creation, thereby improving the plasma channel stability. The supersonic jet is produced by a gas expansion into the reactor chamber through a converging-diverging nozzle that has a hollow inner tube on its axis for both heavy ion and UV laser beam injection.

scholarly journals Transport of heavy-ion beams in a 1 m free-standing plasma channel

2006 ◽  
Vol 24 (1) ◽  
pp. 71-80 ◽  
Author(s):  
S. NEFF ◽  
R. KNOBLOCH ◽  
D.H.H. HOFFMANN ◽  
A. TAUSCHWITZ ◽  
S.S. YU
Keyword(s):  
Fusion Reactor ◽  
Ballistic Transport ◽  
Heavy Ion ◽  
Ion Beams ◽  
Beam Transport ◽  
Free Standing ◽  
Plasma Channels ◽  
Channel Transport ◽  
Stable Plasma ◽  
Heavy Ion Fusion

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 für 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.

scholarly journals Target implosion uniformity in heavy-ion fusion

2016 ◽  
Vol 34 (4) ◽  
pp. 735-741 ◽  
Author(s):  
T. Karino ◽  
S. Kawata ◽  
S. Kondo ◽  
T. Iinuma ◽  
T. Kubo ◽  
...  
Keyword(s):  
Growth Rate ◽  
Physical Quantity ◽  
Dynamic Instability ◽  
Heavy Ion ◽  
Ion Beams ◽  
Instability Growth Rate ◽  
Beam Axis ◽  
Inertial Fusion ◽  
Instability Growth ◽  
Heavy Ion Fusion

AbstractIn this paper, the robustness of the dynamic instability mitigation mechanism is first examined, and then the instability mitigation phenomenon is demonstrated in a deuterium–tritium (DT) fuel target implosion by wobbling heavy-ion beams (HIBs). The results presented here show that the mechanism of the dynamic instability mitigation is rather robust against changes in the phase, the amplitude and the wavelength of the wobbling perturbation applied. In general instability would emerge from the perturbation of the physical quantity. Normally the perturbation phase is unknown, so that the instability growth rate is discussed. However, if the perturbation phase is known, the instability growth can be controlled by a superposition of perturbations imposed actively: if the perturbation is induced by, for example, a driving beam axis oscillation or wobbling, the perturbation phase could be controlled and the instability growth is mitigated by the superposition of the growing perturbations. In this paper, we realize the superposition of the perturbation by the wobbling HIBs’ illumination onto a DT fuel target in heavy-ion inertial fusion (HIF). Our numerical fluid implosion simulations present that the implosion non-uniformity is mitigated successfully by the wobbling HIBs illumination in HIF.

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