本文選題：超強超短激光脈沖　切入點：等離子體　出處：《東北石油大學(xué)》2015年碩士論文

【摘要】：近年來,高能的離子束,尤其的高能質(zhì)子束在質(zhì)子快速成像、癌癥的治療方面以及質(zhì)子加熱等領(lǐng)域發(fā)揮了重要的作用。因此獲得高品質(zhì)的離子束成為專家學(xué)者所不斷追求的目標。因此在過去的幾十年里,物理學(xué)家們一直致力于在尋找更短距離加速粒子方案,期望能在較小的范圍內(nèi)收獲更高的粒子能量。伴隨科技的進步,CPA技術(shù)的迅速發(fā)展,在現(xiàn)有的激光器上已經(jīng)可以獲得飛秒量級的超強超短激光脈沖,這樣的激光所形成的激光場強遠遠超過了原子內(nèi)部的場強。強激光、等離子體二者的相互作用時,往往伴隨著高達GV/m~TV/m量級的強縱向靜電場,科研工作者就可以用這些電場可以來加速電子、質(zhì)子或離子,并采用這種方法開發(fā)小型化的粒子加速器。目前,激光等離子體加速產(chǎn)生質(zhì)子在實驗上已取得一些成果,但在由于相對論效應(yīng)、群體效應(yīng)、湍流等因素的影響,加速處的質(zhì)子束流品質(zhì)不高,所以仍有需要研究工作需要完成。本文基于一維的粒子云網(wǎng)格(Particle-In-Cell,PIC)計算機模擬,通過改變靶的密度,研究靶密度分布對激光等離子體質(zhì)子加速的影響,在本模擬中采用ROOT軟件對所產(chǎn)生的超大數(shù)據(jù)進行處理并產(chǎn)生加速粒子速度分布,更清晰準確的了解到靶密度分布對結(jié)果的影響。在本文中經(jīng)過激光參數(shù),靶參數(shù)的初步篩選,而后對靶形狀進行初步的選擇,確定在一維情況下表現(xiàn)較為出色的密度梯度靶型。在對三種激光脈沖形狀篩選后發(fā)現(xiàn)sin2型的激光同靶相互作用時所產(chǎn)生的質(zhì)子速度較高,而在三種靶中又以凸型密度梯度靶所產(chǎn)生的質(zhì)子束品質(zhì)最好。因此在研究中著重的對sin2型激光與凸型密度梯度靶相互作用進行了研究,在改變靶密度的過程中發(fā)現(xiàn)了一種凸型密度靶與sin2型右旋圓偏振激光相互作用所產(chǎn)生的質(zhì)子束流能量達到316.92 MeV,通過一維PIC模擬,找到了有利于質(zhì)子加速的靶密度分布,從而為激光等離子體質(zhì)子加速實驗研究提供了一定的理論指引。
[Abstract]:In recent years, high energy ion beam, especially the high-energy proton beam in fast imaging and proton proton treatment, heating and other fields of cancer has played an important role. So the ion beam to obtain high-quality experts and scholars have become the pursuit of the goal. So in the past few decades, physicists have been looking for a shorter the distance is expected to accelerate particles, higher energy particles results in a smaller range. With the progress of science and technology, the rapid development of CPA technology, ultrashort laser pulse in the existing laser can obtain femtosecond laser intensity, the formation of such laser is far more than the field inside the atom laser. Two, the interaction of plasma, often accompanied by strong vertical electrostatic field up to the magnitude of GV/m~TV/m, researchers can use the electric field can be accelerated The electron, proton or ion, and using this method to develop miniaturized particle accelerators. Currently, laser plasma acceleration of protons produced some achievements have been obtained in the experiment, but due to relativistic effects, group effect, effect of turbulence and other factors, accelerate the proton beam quality is not high, so there is still a need to work needs to be done. In this paper, based on one-dimensional particle cloud grid (Particle-In-Cell, PIC) computer simulation, by changing the density of the target, study on the effect of target density distribution of laser plasma acceleration of protons in the simulation by ROOT software on large data generated by the processing and accelerate the particle velocity distribution more clearly and accurately understand the target density distribution of the results. In this paper through the preliminary screening of the laser parameters, target parameters, and then carry out the preliminary selection of target shape, identified in the one-dimensional case The density gradient target more outstanding performance. In three to find the laser interaction with the target of the sin2 type proton high speed laser pulse shape screening, proton beam quality in the three target in the convex density gradient generated by the best target. Therefore in the study of a heavy sin2 laser interaction with convex target density gradient were studied in the process of changing the target density was found in a proton density target and convex type sin2 right circularly polarized laser caused by the interaction of beam energy of 316.92 MeV, the one-dimensional PIC simulation, find the target for proton density distribution the speed, in order to provide theoretical guidance for the experimental study of laser plasma proton acceleration.

【學(xué)位授予單位】：東北石油大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TN24

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相關(guān)期刊論文 前2條

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本文編號：1719340