Reduction of Threshold for Laser Fusion Ignition by Nonlinear Force Driven Block Acceleration
| Autor: | B. Malekynia, H. Hora, M. Ghoranneviss, G.H. Miley |
|---|---|
| Rok vydání: | 2009 |
| Předmět: |
Nuclear and High Energy Physics
Fusion Materials science Mechanical Engineering Ion current Plasma Fusion power Space charge Computational physics law.invention Ignition system Acceleration Nuclear Energy and Engineering Physics::Plasma Physics law General Materials Science Atomic physics Inertial confinement fusion Civil and Structural Engineering |
| Zdroj: | Fusion Science and Technology. 56:384-390 |
| ISSN: | 1943-7641 1536-1055 |
| Popis: | Block ignition was proposed recently as a possible alternate approach to fast ignition for ICF fusion. This approach uses a modified petawatt-picosecond (PW-ps) laser pulse shape where the prepulse is strongly suppressed. This results in highly directed plasma blocks due to nonlinear (ponderomotive) force acceleration with space charge neutral ion current densities above 10 11 Amp/cm 2 . This allows ignition of deuterium-tritium targets at densities somewhat above solid state density. However, a key issue has been the need to reduce the extremely high thresholds for the high energy flux densities of the blocks as pointed out in a related theory by Bobin and Chu in 1972. Here we show how the threshold can be reduced by a factor up to 20 by two effects. An important contribution comes from the inhibition factor for thermal conductivity due to electric double layers created in the block process. The second effect is the reduction to the stopping length, giving increased heating by the fusion product alpha due to collective interactions in the blocks. Results from including these effects in a hydrodynamic analysis are presented. The advantage of this approach for an ICF fusion reactor is the relaxed pre-compression requirementfor high gain. |
| Databáze: | OpenAIRE |
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