diff --git "a/3NAzT4oBgHgl3EQfuf1J/content/tmp_files/load_file.txt" "b/3NAzT4oBgHgl3EQfuf1J/content/tmp_files/load_file.txt" new file mode 100644--- /dev/null +++ "b/3NAzT4oBgHgl3EQfuf1J/content/tmp_files/load_file.txt" @@ -0,0 +1,558 @@ +filepath=/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf,len=557 +page_content='arXiv:2301.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content='01691v1 [physics.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content='plasm-ph] 4 Jan 2023 Special behavior of alkali beam emission spectroscopy in low-ion-temperature plasma P.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' Bal´azs1,2, O.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' Asztalos1,2, G.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' Anda2, M.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' Vecsei2, S.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' Zoletnik2, S.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' T.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' A.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' Kumar3, G.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' I.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' Pokol1,2 1Institute of Nuclear Techniques, Budapest University of Technology and Economics, Budapest, Hungary 2Centre for Energy Research, Budapest, Hungary and 3Department of Electrical and Computer Engineering, HSX Plasma Laboratory, University of Wisconsin-Madison, Madison, WI, United States of America Beam emission spectroscopy (BES) is a powerful plasma diagnostic method especially suited for the measurement of plasma density and its fluctuations.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' Designing a BES system for an experimental fusion device is, however, not trivial, and the process can be greatly aided by computer simulations of how a proposed setup would work in the given environment.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' This paper presents such analysis utilizing the RENATE-OD synthetic diagnostic code for a proposed alkali BES system on the HSX stellarator.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' HSX is a device featuring an unusual operating regime in the world of fusion devices due to the low ion temperature and low plasma density.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' It was found that BES shows unusual tendencies in these conditions.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' The relation between beam energy and plasma penetration in low- ion-temperature plasma, together with unique emission features facilitated by low-density plasma, and the underlying reasons behind these features are explored in this paper.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' I.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' INTRODUCTION In the current development stage of fusion technology, plasma diagnostic tools are still much needed to sup- port the validation of various theories and verification of engineering solutions.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' Active diagnostic techniques, when some kind of probing of the plasma is carried out, are especially attractive due to their localized measure- ments.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' Such a system is beam emission spectroscopy (BES), used in several experimental devices, including JET [1], ASDEX Upgrade [2], EAST [3], DIII-D [4], and even small devices like COMPASS [5].' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' This tech- nique probes the plasma with a neutral atomic beam, resulting in the release of light due to interactions with the energetic plasma particles.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' The wavelength of this light is characteristic to the beam material, which can be one of the hydrogen isotopes in larger beams, or alkali metals (lithium, sodium) in the small diagnostic beams.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' The intensity of the emitted light is highly dependent on the plasma density, which combined with the ability of continuous operation makes the technique ideal for spa- tially and temporally resolved density fluctuation mea- surements.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' This is especially true for alkali diagnostic beams, with the added benefit of the emission spectrum being well distinguishable from the background.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' The lim- itation of this type of BES is the generally short, few cen- timeters long penetration into the plasma, but the region spanned by this limitation is still interesting in terms of transport and magnetohydrodynamic phenomena.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' The construction of a BES system requires careful de- sign due to geometric restrictions and the desire to max- imize the collectable photon flux [6].' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' As an aid for this problem, one can utilize BES simulation codes designed to produce synthetic measurements under the specific plasma conditions of the device in question.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' Based on the data of such simulations it is possible to analyze the expected performance of the diagnostic system, help- ing the engineers to balance between design trade-offs.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' RENATE-OD [7] (Rate Equations for Neutral Alkali- beam TEchnique - Open Development) is an open-source Python package developed for this purpose.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' This code solves rate equations to calculate the population of each atomic level considered in the calculations, from which the emissivity of the beam is acquired through the spon- taneous transition rate for the observed spectral line.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' With the ability to accurately predict the performance of a BES system under design, it is possible to dynami- cally test various injection and observation configurations for optimal operation.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' RENATE-OD and its precursor, RENATE [8], has al- ready been utilized in multiple projects regarding BES systems.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' The code’s capabilities have been validated with KSTAR measurements [9, 10], it was the main tool for a feasibility study of a BES system for JT60-SA [11], and aided the design of lithium beam diagnostics on EAST [12].' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' Recently, we performed a feasibility study for the HSX (Helically Symmetric eXperiment) stellarator.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' This device is operated by the Electrical and Computer Engineering department of the University of Wisconsin- Madison, with the aim of investigating transport, tur- bulence, and confinement in a quasi-helically symmetric magnetic field [13].' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' It is a small device with average ma- jor and minor radii of 1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content='2 m and 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content='15 m, respectively.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' The magnetic field is produced by copper coils, allowing dis- charges up to only 100 ms long, and a maximum on-axis magnetic field of 1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content='25 T.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' The plasma density achievable in the device is on the order of a few times 1018 m−3, which is relatively low compared to other fusion-related plasma experiments.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' As a consequence, the electrons heated by electron cyclotron resonance are poorly coupled to the ions, resulting in an electron and ion population with dis- parate temperatures.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' Throughout this paper, we treated the ion temperature as constant at 50 eV throughout the machine, while the electron temperature was prescribed with a peaked profile reaching a maximum of 2.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content='5 keV [14].' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' As of now, the device does not have a BES system, therefore we performed a feasibility study to explore how the technique would perform under such conditions.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' Part of this process was to simulate the evolution of lithium 2 (Li) and sodium (Na) beams across low-density and low- ion-temperature plasma profiles as described before.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' We observed that both the beam density and emissivity can behave unusually under these circumstances.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' Notably, a beam with low energy could be less attenuated than a high-energy beam, and changes in the electron tem- perature are more visible in the emission compared to measurements in high-density plasma.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' The reasons be- hind these phenomena are explored in this work.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' We also note that these plasma conditions are not exclusive to HSX, since they can be regularly found in the diver- tor region of larger fusion devices.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' Measurement of these regions by BES is an unexplored area, which warrants further efforts for investigation.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' The basic methodology of the calculations performed by RENATE-OD are presented in Chapter II, then in Chapter III the unusual effects found in beam attenua- tion and emission are presented together with their ex- planation.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' Finally, in Chapter IV the findings and their relevance are summarized.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' II.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' CALCULATIONS To simulate the density and emission of an atomic beam along its path, RENATE-OD solves the rate equa- tions describing the population of the valence electrons of the beam atoms on the most populated atomic levels.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' In the case of alkali atoms, the considered levels are the l-resolved states reachable by the valence electron up to 4.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content='5 eV in the case of lithium, which includes 2s, 2p, 3s, 3p, 3d, 4s, 4p, 4d, 4f, and up to 4.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content='1 eV for sodium, in- cluding 3s, 3p, 3d, 4s, 4p, 4d, 4f, 5s.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' The populations of the levels evolve due to interactions with the plasma components.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' The simulated light emission is governed by collisional excitation to the higher energy levels followed by spontaneous emission.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' The attenuation of the beam is contributed to the beam atoms becoming charged, and therefore redirected by the perpendicular magnetic field component.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' This can happen through collisional ioniza- tion or charge exchange with plasma ions, and we refer to the sum of these processes as electron loss.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' The simu- lation does not include interaction between beam atoms due to being negligible compared to beam-plasma inter- actions.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' It is also assumed that only the valence electrons participate in the relevant processes, and initially, all of them are in the ground state.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' The atomic levels can gain or lose electrons through multiple channels.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/3NAzT4oBgHgl3EQfuf1J/content/2301.01691v1.pdf'} +page_content=' For example, if we denote the popu- lation density of a particular level with ni, we can write its losses due to excitation by electrons in the form of �dni dt � el,exc = −nine � i