本文選題：強(qiáng)流重離子束 + 束靶相互作用�。� 參考：《中國(guó)科學(xué)院研究生院(近代物理研究所)》2016年博士論文

【摘要】：高能量密度物質(zhì)廣泛存在于宇宙星體中,且是慣性約束聚變所必經(jīng)的極端物質(zhì)狀態(tài),實(shí)驗(yàn)上對(duì)高能量密度物質(zhì)物理性質(zhì)的研究不僅對(duì)天體物理意義重大,同時(shí)也是慣性約束聚變研究中擬解決的的關(guān)鍵科學(xué)問題。重離子束由于其特殊的能量沉積方式,作為驅(qū)動(dòng)源為高能量密度物理實(shí)驗(yàn)研究開辟了一條新道路。國(guó)際大科學(xué)工程FAIR及HIAF已將強(qiáng)流重離子束驅(qū)動(dòng)的高能量密度物理列為科學(xué)目標(biāo)之一。目前FAIR已經(jīng)處于工程建設(shè)中,而HIAF工程項(xiàng)目也已獲批,將要啟動(dòng),所以相關(guān)數(shù)值模擬計(jì)算工作必須先行一步為加速器工程建設(shè)及實(shí)驗(yàn)方案提供科學(xué)及技術(shù)參考。本論文中選取高能量密度物理前期研究中的兩個(gè)關(guān)鍵問題進(jìn)行了深入的研究及討論,分別是高能量密度物理終端的束靶相互作用模擬及加速器建設(shè)過程中的動(dòng)態(tài)真空問題。除此之外,本論文中還對(duì)重離子與固體相互作用過程中的微觀機(jī)制做了深入研究。具體研究?jī)?nèi)容及主要結(jié)果如下:1、系統(tǒng)性地定量地研究了強(qiáng)流重離子束與靶相互作用過程中束流的能量,束斑,脈寬以及靶的結(jié)構(gòu)對(duì)產(chǎn)生的高能量密度物質(zhì)狀態(tài)的影響,結(jié)果表明:束流直接加熱靶物質(zhì)時(shí),物質(zhì)中可以達(dá)到的溫度與單位沉積能量幾乎呈線性關(guān)系;物質(zhì)的流體運(yùn)動(dòng)大約開始在束流加載后的幾十個(gè)ns內(nèi),所以束流脈寬超過一百ns會(huì)影響束流的沉積效率;采用不同的束靶耦合方案可以滿足我們對(duì)高能量密度物質(zhì)狀態(tài)的各種需求,比如若想在物質(zhì)中產(chǎn)生極高壓狀態(tài),環(huán)形空心束作用雙層靶外層對(duì)內(nèi)層材料進(jìn)行低熵壓縮是首選,可以將物質(zhì)密度進(jìn)行上百倍壓縮;若想產(chǎn)生極高溫狀態(tài),可采用圓斑束加熱雙層靶,內(nèi)層材料在束流直接加熱以及外層沖擊波壓縮共同作用下生成極高溫狀態(tài)。2、針對(duì)HIAF提出的束流參數(shù),模擬了三種典型的束靶耦合結(jié)構(gòu)下所產(chǎn)生的極端物質(zhì)狀態(tài),結(jié)果表明:利用HIAF一期工程項(xiàng)目B-Ring(400ns脈寬)提供的束流,實(shí)驗(yàn)上雖然可以產(chǎn)生高能量密度物質(zhì),但是模擬計(jì)算表明靶被最優(yōu)壓縮的時(shí)刻處于束流脈寬內(nèi)一百多納秒,意味著多一半的束流沒有被有效利用,而如果將束流壓縮至50ns,實(shí)驗(yàn)上的物質(zhì)狀態(tài)參數(shù)可以被提高一個(gè)量級(jí),這樣實(shí)驗(yàn)上很有可能會(huì)達(dá)到高能量密度物理的強(qiáng)沖擊波區(qū)域;二期工程C-Ring一旦建成,實(shí)驗(yàn)上沖向高能量密度物理的強(qiáng)輻射區(qū)域也是非常有希望的。3、以FAIR工程為例,模擬估算了強(qiáng)流重離子束作用下靶的氣化過程引起的終端動(dòng)態(tài)真空變化,通過在現(xiàn)有束線上對(duì)壓力波傳輸進(jìn)行測(cè)量校準(zhǔn)了動(dòng)態(tài)真空蒙特卡羅模擬程序。結(jié)果顯示:FAIR工程高能量密度物理終端現(xiàn)有設(shè)計(jì)無法抵擋靶的氣化對(duì)真空的影響,對(duì)整個(gè)加速器是一個(gè)安全隱患,但是模擬結(jié)果給出的氣化壓力波傳輸所需的時(shí)間量級(jí)提供了解決方法,即在終端連接處附件安裝一個(gè)毫秒量級(jí)快閥。4、超高真空環(huán)境下加速器環(huán)內(nèi)的殘余氣體與束流作用導(dǎo)致束流偏轉(zhuǎn)與管壁碰撞,同時(shí)釋放更多殘余氣體這一效應(yīng)使重離子束單脈沖離子數(shù)無法超過109,為了解決這一難題,GSI-SIS18利用一個(gè)準(zhǔn)直器降低離子與管壁碰撞中解吸至真空中的粒子數(shù)目將束流強(qiáng)度提高了一個(gè)量級(jí),本文介紹了針對(duì)FAIR-SIS100的低溫準(zhǔn)直器研究,初步實(shí)驗(yàn)測(cè)量結(jié)果顯示發(fā)現(xiàn)低溫條件下,物質(zhì)的行為與常溫下完全不同,這一方面還需要再進(jìn)一步的研究。5、實(shí)驗(yàn)上測(cè)量了高電荷態(tài)離子與固體(Z=14-79)相互作用過程中的X射線發(fā)射,分析發(fā)現(xiàn)炮彈離子X射線發(fā)射產(chǎn)額隨靶原子序數(shù)變化呈周期性震蕩結(jié)構(gòu),近能級(jí)匹配區(qū)域碰撞系統(tǒng)中X射線發(fā)射存在非常明顯的電荷態(tài)效應(yīng),這些都表明了能級(jí)匹配區(qū)域分子軌道躍遷機(jī)制的重要性�；谟^測(cè)到的電荷態(tài)效應(yīng)及分子軌道躍遷理論,推出了高電荷態(tài)離子在固體中的平衡時(shí)間約7fs。
[Abstract]:High energy density material exists widely in cosmic stars, and is an extreme material state which is required by inertial confinement fusion. The study of physical properties of high energy density materials is not only important to astrophysics, but also the key scientific problem to be solved in the study of inertial confinement fusion. Heavy ion beam is due to its special characteristics. The energy deposition method, as the driving source, has opened a new road for the physical experiment of high energy density. FAIR and HIAF have listed the high energy density physics of the heavy ion beam driven by the strong current and heavy ion beam as one of the scientific goals. At present, the FAIR has been in the engineering construction, and the HIAF project has also been approved, so the phase will be started. In this paper, two key problems of high energy density physics are studied and discussed in this paper, which are the simulation of the beam target interaction of high energy density physical terminals and the construction of the accelerator. In addition, the microscopic mechanism of the interaction between heavy ions and solid is also studied in this paper. The main results are as follows: 1, the beam energy, beam spot, pulse width and target junction in the interaction process of strong current heavy ion beam and target are systematically studied. The effect of the structure on the state of high energy density material shows that when the beam is directly heated, the temperature can be almost linear with the unit deposition energy, and the fluid movement of the material begins in the dozens of NS after the beam loading, so the beam pulse width over one hundred ns will affect the deposition efficiency of the beam. By using a different beam target coupling scheme, we can meet various requirements for the state of high energy density material. For example, if we want to produce extremely high pressure state in the material, the low entropy compression of the inner layer is the first choice for the double layer target outer layer of the annular hollow beam, and the density of the material can be compressed by 100 times, and if we want to produce very high temperature state, A circular spot beam can be used to heat double layers of target, and the inner material generates extremely high temperature state.2 under the joint effect of beam direct heating and external shock wave compression. According to the beam parameters proposed by HIAF, the extreme material state produced by three typical beam target coupling structures is simulated. The results show that the HIAF phase I project B-Ring (400ns pulse) is used. The beam provides a high energy density material in experiment, but the simulation results show that the optimal compression time of the target is more than 100 nanoseconds in the beam pulse width, which means that more than half of the beam is not used effectively, and if the beam is compressed to 50ns, the actual state parameters of the material can be improved by one order of magnitude. A strong shock wave region with high energy density physics is likely to be reached in the sample experiment; once the two project C-Ring is built, the strong radiation area of high energy density physics is also a very promising.3. Taking the FAIR project as an example, the dynamic vacuum change of the terminal caused by the gasification process of the target under the action of the heavy ion beam is simulated. The dynamic vacuum Monte Carlo simulation program is calibrated by measuring the pressure wave transmission on the existing beam line. The results show that the existing design of the FAIR engineering high energy density physical terminal can not resist the effect of the gasification of the target on the vacuum, and it is a safety hazard to the whole accelerator, but the pressure wave transmission given by the simulation results is given. The required time magnitude provides a solution to the installation of a millisecond fast valve.4 at the terminal attachment. The residual gas and beam flow in the accelerator ring causes the beam deflecting to collide with the tube wall in the ultra high vacuum environment, and the release of more residual gases can not exceed 109 of the single pulse ion number of the heavy ion beam. In order to solve this problem, GSI-SIS18 uses a collimator to reduce the number of particles in the collision between the ion and the tube wall. The intensity of the beam is increased by one order. This paper introduces the study of the low temperature collimator for FAIR-SIS100. The preliminary experimental results show that the behavior of the matter at low temperature is completely different from the normal temperature. In this respect, we also need to further study.5, experimentally measuring the X ray emission from the interaction between highly charged ions and solid (Z=14-79). The analysis shows that the X ray emission yield of the projectile ions is periodically oscillating with the change of the number of target atoms, and the X ray emission of the near energy level matching region collision system is very bright. The significant charge state effect shows the importance of the molecular orbital transition mechanism in the energy level matching region. Based on the observed charge state effect and the molecular orbital transition theory, the equilibrium time of the highly charged ions in the solid is about 7fs.

【學(xué)位授予單位】：中國(guó)科學(xué)院研究生院(近代物理研究所)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2016
【分類號(hào)】：O572

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 Yongtao Zhao;Rui Cheng;Yuyu Wang;Xianming Zhou;Yu Lei;Yuanbo Sun;Ge Xu;Jieru Ren;Lina Sheng;Zimin Zhang;Guoqing Xiao;;High energy density physics research at IMP,Lanzhou, China[J];High Power Laser Science and Engineering;2014年04期

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本文編號(hào)：1822086