Core heating properties in FIREX-I-influence of cone
Core heating properties in FIREX-I-influence of cone
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DOI：
10.1088/0741-3335/51/1/014002
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发表时间：
2009-01-01
影响因子：
2.2
通讯作者：
Mima, K.
中科院分区：
文献类型：
--
作者：
Johzaki, T.;Sentoku, Y.;Mima, K.
在一维耦合PIC和Fokker-Planck模拟的基础上，研究了不同锥体材料在锥形引导快速点火亚点火类实验中的核心加热特性。当使用Au作为锥尖的材料时，Au原子在与加热脉冲的相互作用中在几百飞秒内电离到高电荷态。由于极端的光子压力，在密度斜率变陡后，脉冲开始直接与固体密度锥尖相互作用。此外，返回电流中的电子被高度电离的Au离子强烈散射。在这种情况下，加热激光与快速电子的能量耦合可能会急剧下降。在锥尖输运过程中，由于碰撞阻力和Au离子的散射，产生的快速电子束质量下降。其结果是，加热激光对岩心的能量耦合效率降低，岩心加热迅速饱和。我们提出将CH作为锥尖的替代材料，以减少碰撞缺陷。研究发现，在10(20)wcm（-2）强度的脉冲加热1 ps后，CH锥尖的压缩CD核心的温度上升幅度是Au锥尖的两倍。
On the basis of one-dimensional coupled PIC and Fokker-Planck simulations, the core heating properties of different cone materials for sub-ignition class experiments of the cone-guiding fast ignition have been studied. When Au is used as a material of the cone tip, the Au atoms ionize to a high charge state during the interaction with a heating pulse in a few hundreds of femtoseconds. Because of the extreme photon pressure, the pulse starts to interact directly with a solid-density cone tip after the density slope is steepened. In addition, the electrons in the return current are strongly scattered by the highly ionized Au ions. In such a situation, the energy coupling of the heating laser to the fast electrons could drop drastically. During the transport in the cone tip, the quality of the generated fast electron beam deteriorates due to the collisional and resistive drags and the scattering by the Au ions. As a result, the core heating gets saturated quickly and the energy coupling efficiency of the heating laser to the core decreases. We proposed CH as an alternative material of cone tip to reduce the collisional defects. It is found that in comparison with the Au cone tip, a twice higher rise in temperature of a compressed CD core has been achieved with the CH cone tip after 1 ps heating by a 10(20) W cm(-2) intensity pulse.