scholarly journals Volume Ignition in Pellet Fusion to Overcome the Difficulties of Central Ignition

1987 ◽  
Vol 42 (10) ◽  
pp. 1239-1240a ◽  
Author(s):  
Heinrich Hora
Keyword(s):  
Solid State ◽  
Analytical Formula ◽  
Spark Ignition ◽  
Laser Fusion ◽  
Volume Compression ◽  
Volume Ignition

Since C. Yamanaka et al. demonstrated that the best fusion gains from laser irradiated pellets result only when central shocks are avoided and an ideal volume compression is achieved, the problems o f the central (spark) ignition with necessary densities of 1000 times the solid state may be overcome. Based on an analytical formula of volume ignition, the new conditions should provide reactor adequate laser fusion with compression to 50 to 100 times solid state.

scholarly journals Volume ignition of laser driven fusion pellets and double layer effects

1988 ◽  
Vol 6 (2) ◽  
pp. 163-182 ◽  
Author(s):  
L. Cicchitelli ◽  
S. Eliezer ◽  
M. P. Goldsworthy ◽  
F. Green ◽  
H. Hora ◽  
...  
Keyword(s):  
Electric Fields ◽  
Inertial Confinement Fusion ◽  
Laser Pulses ◽  
Spark Ignition ◽  
State Density ◽  
Double Layers ◽  
Inertial Confinement ◽  
Confinement Fusion ◽  
Volume Compression ◽  
Volume Ignition

The realization of an ideal volume compression of laser-irradiated fusion pellets (by C. Yamanaka) opens the possibility for an alternative to spark ignition proposed for many years for inertial confinement fusion. A re-evaluation of the difficulties of the central spark ignition of laser driven pellets is given. The alternative volume compression theory, together with volume burn and volume ignition (discovered in 1977), have received less attention and are re-evaluated in view of the experimental verification by Yamanaka, generalized fusion gain formulas, and the variation of optimum temperatures derived at self-ignition. Reactor-level DT fusion with MJ-laser pulses and volume compression to 50 times the solid-state density are estimated. Dynamic electric fields and double layers at the surface and in the interior of plasmas result in new phenomena for the acceleration of thermal electrons to suprathermal electrons. Double layers also cause a surface tension which stabilizes against surface wave effects and Rayleigh–Taylor instabilities.

Measured laser fusion gains reproduced by self-similar volume compression and volume ignition for NIF conditions

1998 ◽  
Vol 60 (4) ◽  
pp. 743-760 ◽  
Author(s):  
HEINRICH HORA ◽  
H. AZECHI ◽  
Y. KITAGAWA ◽  
K. MIMA ◽  
M. MURAKAMI ◽  
...  
Keyword(s):  
Detonation Front ◽  
Adiabatic Compression ◽  
The Self ◽  
Laser Fusion ◽  
National Ignition Facility ◽  
Self Similarity ◽  
Spherical Detonation ◽  
Self Similar ◽  
Volume Compression ◽  
Volume Ignition

The recent high core gains of 29% in laser fusion experiments at the LLE Rochester are evaluated and compared with related earlier measurements where surprisingly the self-similarity model for volume compression provides a common description. This is a proof that the isentropic conditions of stagnation-free compression were mostly fulfilled at the optimized experimental gains, in contrast to highly entropy-producing shock and central spark conditions. Some projections are given of how these results may be generalized to volume ignition for the parameters of the NIF (National Ignition Facility). The proof of stagnation-free volume compression for the best laser fusion gains indicates the advantages of volume ignition, which not only is ‘robust’ and simply follows the natural adiabatic compression, but also is much less sensitive to instabilities and mixing. However, its essential advantage is that it is free from symmetry problems – in contrast to spark ignition, with its spherical detonation front.

Development of the diode-pumped solid state laser and its application to laser fusion and industry

1998 ◽  
Author(s):  
Sadao Nakai ◽  
Yasukazu Izawa ◽  
Masahiro Nakatsuka ◽  
Masanobu Yamanaka ◽  
Yasuji Kozaki ◽  
...  
Keyword(s):  
Solid State ◽  
Solid State Laser ◽  
Laser Fusion ◽  
State Laser ◽  
Diode Pumped

scholarly journals Single event laser fusion using ns-MJ laser pulses

2005 ◽  
Vol 23 (4) ◽  
pp. 453-460 ◽  
Author(s):  
GEORGE H. MILEY ◽  
H. HORA ◽  
F. OSMAN ◽  
P. EVANS ◽  
P. TOUPS
Keyword(s):  
Fusion Reaction ◽  
Laser Pulses ◽  
Laser Fusion ◽  
Detailed Knowledge ◽  
Single Event ◽  
Direct Drive ◽  
Laser Target ◽  
Laser Systems ◽  
Near Term ◽  
Volume Ignition

Studies of single-event laser-target interaction for fusion reaction schemes leading to volume ignition are discussed. Conditions were explored where single-event ns-laser pulses give rise to temperatures sufficient for volume ignition. Thus, ignition is possible, particularly if X-ray reabsorption is sufficiently high. Unfortunately, this scheme requires laser pulses with energies above 5 MJ and target densities of compressed DT above 1000 g/cm−3. Both requirements are quite demanding for near term systems. Nevertheless the present state technology and the detailed knowledge about volume ignition at direct drive are a basis. Systems as NIF or LMJ can well confirm these physics-clarified conditions and the technology for large laser systems with sufficient repetition rate and for a drastic reduction of the size and costs is necessary and possible and by physics similar to the known reductions in transistor development.

scholarly journals Volume compression and volume ignition of laser driven fusion pellets

1989 ◽  
Vol 7 (3) ◽  
pp. 511-520 ◽  
Author(s):  
G. Kasotakis ◽  
L. Cicchitelli ◽  
H. Hora ◽  
R. J. Stening
Keyword(s):  
Close Agreement ◽  
Initial Temperature ◽  
Fusion Energy ◽  
The Self ◽  
Fusion Reactions ◽  
Nuclear Fusion Reactions ◽  
Volume Compression ◽  
Volume Ignition ◽  
Additional Stimulation ◽  
Stimulation Of

Volume compression and volume ignition of laser compressed pellets has an enormous advantage against spark ignition since the alpha self-heat substantially contributes as an additional stimulation of nuclear fusion reactions. We present here improved computations of volume ignition in agreement with the classical fact that the generated fusion energy is larger than the bremsstrahlung energy in DT only at temperatures above 4·5 keV. This result is in very close agreement with Kidder's (1974) values, and in agreement with recent computations of Mimaet al.(1987). The extension of these calculations to higher densities and input energies results in the self-absorption of bremsstrahlung at an initial temperature of about 1 keV only, much below the classical 4·5 keV. A fuel burnup fraction above 80% is shown to be possible.

scholarly journals Extraordinary strong jump of increasing laser fusion gains experienced at volume ignition for combination with NIF experiments

2013 ◽  
Vol 31 (2) ◽  
pp. 229-232 ◽  
Author(s):  
Heinrich Hora
Keyword(s):  
Nuclear Fusion ◽  
Fusion Energy ◽  
Laser Fusion ◽  
Energy Needs ◽  
The World ◽  
Volume Ignition

AbstractAiming breakeven for nuclear fusion energy needs a more than 1000 times higher fusion gain. This may be achieved as the anomalously high jump of gains known from the discovery of volume ignition since 1978. This is considered for combination with the present most advanced experiments at the world highest class laser of NIF.

Design of Laser Fusion Reactordriven by Laser-Diode-Pumped Solid State Laser

1992 ◽  
Vol 21 (3P2A) ◽  
pp. 1460-1464 ◽  
Author(s):  
Y. Kitagawa ◽  
K. Mima ◽  
H. Takabe ◽  
M. Yamanaka ◽  
K. Naito ◽  
...  
Keyword(s):  
Solid State ◽  
Laser Diode ◽  
Solid State Laser ◽  
Laser Fusion ◽  
State Laser ◽  
Diode Pumped

Origins of Hydrocarbon Emissions from a Multi-Fuel, Torch Ignition Assisted Direct Injection Engine

1986 ◽  
Vol 200 (1) ◽  
pp. 21-30 ◽  
Author(s):  
J A LoRusso ◽  
P H Havstad ◽  
E W Kaiser ◽  
W G Rothschild
Keyword(s):  
Chromatographic Analysis ◽  
Small Volume ◽  
Direct Injection ◽  
Single Point ◽  
Spark Ignition ◽  
Hydrocarbon Emissions ◽  
High Hydrocarbon ◽  
Hc Emissions ◽  
Volume Ignition ◽  
Tracer Experiments

Unthrottled, direct injection ignition assisted (DI–IA) engines have demonstrated DI diesel efficiencies and multi-fuel capabilities. However, high hydrocarbon (HC) emissions have been a problem with this concept. Torch ignition, provided by a separately fuelled small volume prechamber with spark ignition, was applied as a research tool to define the benefits of large volume ignition for controlling HC emissions. Torch ignition was found to be beneficial for HC control relative to the use of single point spark ignition; however, HC levels were higher than those observed from a DI diesel using low emissions technology. To assist in investigating the cause of the higher HC emissions, tracer experiments were conducted to verify that prechamber combustion characteristics did not contribute significantly to the total exhaust HC emissions. Separate, but similar, fuels were used for the main chamber and prechamber. Through gas chromatographic analysis of the major exhaust HC species, prechamber combustion was found to contribute substantially less than 20 per cent to the overall HC emissions for the engine conditions studied.

An Advanced Fuel Laser Fusion and Volume Compression ofp-11B Laser-Driven Targets

1991 ◽  
Vol 19 (1) ◽  
pp. 43-51 ◽  
Author(s):  
George H. Miley ◽  
Heinrich Hora ◽  
Lorenzo Cicchitelli ◽  
Gregorios V. Kasotakis ◽  
Robert J. Stening
Keyword(s):  
Laser Fusion ◽  
Advanced Fuel ◽  
Volume Compression
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