Measurement of Coulomb Logarithm in Heavy-ion-Plasma Interaction by Using Low-Energy Protons

为了测量重离子与等离子体相互作用中的库仑对数，研制了一台专用的低能激光等离子体离子源加速器。获得了1μA以上的束流强度，这是进行束-等离子体相互作用实验所必需的。还研制了静电四极透镜用于束流聚焦。在现有的加速器设施中，建造了这种低能机器的专用束线。一束120 keV的质子束被成功地注入到现有的束线。为了利用TOE（飞行时间）法测量能量损失，我们研制了一种基于重入式RE谐振腔的光束聚束器。利用该脉冲系统获得了脉宽小于1 ns的聚束。作为初步的实验，我们测量了120 keV的质子在薄碳箔使用该脉冲系统的能量损失。测得的阻止本领与评价的数据表一致。利用该低能加速器系统，我们利用激光产生的等离子体靶进行了束-等离子体相互作用实验。然而，由于束流位置监测器的灵敏度不足以检测到单次激发的脉冲束，束流在真空室中传输到靶等离子体并不成功。在使用这种低能机器进行实验的同时，我们对不同电荷状态的高能重离子的能量损失进行了实验，以评估库仑对数。用He^2+束成功地测量了z箍缩放电等离子体中能量损失的库仑对数。我们还开发了一个分子动力学的计算机程序来分析能量损失过程。数值模拟了低能高电荷态离子与冷终止等离子体相互作用的非线性效应。

For the measurement of Coulomb logarithm in heavy-ion-plasma interactions, a dedicated low-energy accelerator equipped with a laser-plasma ion source was developed and tested. We obtained beam intensities over 1μA, which was necessary for the beam-plasma interaction experiment. Also a electrostatic quadrupole lens was developed for the beam focusing. In the existing accelerator facility, a dedicated beam line of this low-energy machine was constructed. A 120 keV proton beam was successfully injected into the existing beam line. For the energy loss measurement by a TOE (Time Of Flight) method, we developed a beam buncher based on a reentrant RE resonator cavity. By using this beam pulsing system, we obtained a bunched beam with a duration of < 1ns. As a preliminary experiment, we measured the energy loss of 120 keV protons in a thin carbon foil using this pulsing system. The measured stopping power was consistent with an evaluated data table. By using this low-energy accelerator system, we performed a beam-plasma interaction experiment using a laser-produced plasma target. However, the beam transport to the target plasma in the vacuum chamber was not successful, because the sensitivity of the beam position monitor was not enough to detect the single-shot pulsed beam. In parallel with the experiments using this low-energy machine, we performed experiments on the energy loss of high-energy heavy ions with different charge states in order to evaluate the Coulomb logarithm. By using a He^<2+> beam, the Coulomb logarithm concerning the energy loss in a z-pinch discharge plasma was successfully measured. Also we developed a molecular dynamics computer code to analyze the energy loss process. We numerically observed nonlinear effects for the interaction between low-energy highly-charged ions and cold demise plasmas.