Simulation of runaway electrons with MHD modes
( Dr. Masatoshi Yagi / National Institute for Quantum and Radiological Science and Technology, (QST), Japan )
<專題討論>2017/11/9(四)14:10綜合大樓2樓48218教室演講
Dynamics of runaway electrons in the presence of macroscopic MHD instabilities is studied. Generation of massive runaway beam currents has become a crucial issue for the development of reliable disruption mitigation schemes in ITER. A difficulty arises in a large gap of the avalanche growth gain between present tokamaks and ITER, which prevents us from a straightforward extrapolation of the experimental data towards disruptions with 10MA-order plasma currents. Therefore – in addition to experimental demonstration of runaway mitigation – the development of numerical simulations increases its importance. To clarify possible effects of MHD modes on runaway electron generation, we have applied a nonlinear reduced fluid model [1] for long- term simulations of runaway generation scenario in a post-disruption plasma. In a plasma unstable to resistive kink modes, the coupling between MHD modes, runaway electrons, and electric fields becomes important. It is shown that seed electrons can be enhanced with inductive electric fields and the final runaway beam profile develops to be consistent with the resistive MHD stability [2]. For exploring the possibility of runaway suppression, magnetic and orbit stochasticity is suggested to cause radially global transport of runaway electrons [3].
邁向公職之路－評估與選擇
汪德彥 (交通部民用航空局 飛航服務總臺 北部飛航服務園區 臺北航空通信中心)
<專題討論>2017/11/2(四)14:10綜合大樓2樓48218教室演講
介紹公職領域。
當對個人職涯產生茫然或是生活與工作無法取得平衡，公職就是可以考慮的一個選擇。但是準備公職是一個對自己個性的磨練與考驗，如何能在短時間考上公職，減輕自己的負擔是另一個需要考慮的重點。所以當下定決心考試後，如何擬定策略，達成目標，才是需要時間思考的。
| 附件: 20171102 汪德彥.pdf
什麼是太空天氣? What is Space Weather ?
江致宇 博士候選人( 成大電漿所 )
<專題討論>2017/10/26(四)14:10綜合大樓2樓48218教室演講
近年來，隨著太空科技的日新月異，人類對太空探索和研究已從過去為了解決單一議題，擴大成為整體性太空環境的監測和討論，尤其是會影響人類生活的地球磁層到電離層區域。而想了解太空天氣，學習"電漿"絕對是入門的基本條件，因為從地球大氣層以上，幾乎都是電漿的天下，所有影響太空天氣的活動，也都必須從電漿物理出發。所以這次的演講課題，將跟大家說明太空天氣的源頭在哪裡? 在磁層中有哪些的動力學驅動機制? 以及最後在電離層當中所呈現的結果是什麼? 歡迎大家一起來學習與討論。
| 附件: 20171026 江致宇博士候選人.pdf
In-situ plasma measurements in the Earth’s ionosphere
方惠寬 博士 ( 成大電漿所 )
<專題討論>2017/10/19(四)14:10綜合大樓2樓48218教室演講
Measurements of plasma are fundamental for space physics, especially for space weather. Recently, giant progress of the CubeSat technologies greatly lowers the barrier to insert a satellite into a lower earth orbit for space exploration. Satellite constellation missions consisting of tens of CubeSats is planned and launched. These missions provide multi-point measurements and make it possible to separate spatial and temporal effects regarding couplings between ionosphere, atmosphere and even lithosphere. And the altitude of these missions are rarely explored by conventional satellites because of large air drag and short mission lifetime. In addition to Cubesat missions, simultaneous multi-instrument measurements onboard sounding rockets aiming for the plasma characteristic investigations in the ionosphere D layers, which is the least-explored region in the ionosphere, is planned. In this presentation, the plasma diagnostic techniques onboard CubeSats and sounding rockets will be introduced. The design concepts of the solar EUV probe onboard the Phoenix CubeSat in QB50 mission and the “Mesosphere and Ionosphere Plasma Exploration complex (MIPEX)” instrument onboard the NCKU sounding rocket, which is planned to be launched in 2020, will be shown. These experiments can provide unique high-quality data of the plasma environment to explore the ion distribution and the electrodynamic processes in the Ionosphere D, E layers.
| 附件: 20171019 方惠寬博士.pdf
大氣電學-從高空短暫發光現象到大氣電離層垂直耦合 Atmospheric electricity - From transient luminsous events to a vertical coupling in the Atmosphere–Ionosphere system
陳炳志 副教授 ( 成大電漿所 )
<專題討論>2017/10/12(四)13:30綜合大樓2樓48218教室演講
大氣電學主要是研究地球大氣內的電荷流動，在電離層與地表間的電荷流動構成了循環，形成大域電路。大域電路主要由閃電所驅動，涵蓋了許多大氣內有趣的放電現象。1990年首次發現的高空短暫發光現象是大氣電學領域近年的重要研究課題，在本演講中將介紹高空短暫發光現象以及福衛二號高空大氣閃電影像儀(ISUAL)近年來在此領域的重要成果。在高空短暫發光現象的基礎上，我們也嘗試連接大氣層電離層耦合的相關研究，希望能夠了解閃電與高空短暫發光現象對於高層大氣的影響，相關的研究與進展也會一併介紹。
| 附件: 20171012 陳炳志副教授.pdf
ERG: Ongoing Japan-Taiwan Collaborative Effort to Explore the Radiation Belts
談永頤 教授 ( 成大電漿所 )
<專題討論>2017/9/28(四)14:10綜合大樓2樓48218教室演講
The ERG (Energization and Radiation in Geospace) satellite, nicknamed "Arase", was launched at 20:00 Japan Standard Time on December 20, 2016 from Uchinoura, Japan. The mission is a collaboration between Japan and Taiwan, as one of the instruments aboard the Japanese satellite, LEP-e (Low-Energy Particle experiments - Electron analyzer), was developed by a team in Taiwan that featured the joint effort by Academia Sinica and National Cheng Kung University. The mission aims to investigate the dynamics in the inner magnetosphere, particularly the Van Allen Radiation Belts where the existence of highly energetic particles is common, with the primary goal to understand the acceleration and loss mechanisms of such energetic particles, especially electrons with energies in the relativistic range. The satellite mission is part of the ERG project, which integrates data analyses and simulations based on the satellite measurements and ground-based network observations. With conjugated ground observations complementing measurements by a variety of instruments on the satellite for electromagnetic fields as well as ions and electrons of wide ranges of energy, the ERG project has the potential to contribute to space science research beyond its primary objective.
| 附件: 20170928 談永頤教授.pdf
Fusion in a Staged Z-Pinch
Dr. Frank J. Wessel / Magneto-Inertial Fusion Technologies, Inc., Tustin, CA, USA )
<專題討論>2017/9/21(四)14:10綜合大樓2樓48218教室演講
Abstract：
The Staged Z-pinch is a fusion concept involving the implosion of a high-atomic-number liner onto a pre-magnetized, fusible-target plasma. The concept emerged from liner-driven, flux-compression experiments, wherein a fiber optic, coaxial with the pinch, was used to measure the magnetic-field intensity. Current induced on the fiber’s exterior was observed to couple a pressure impulse that caused the fiber to become birefringent and loose signal [1]. The resulting generalized description for the SZP included azimuthal- and axial-magnetic fields and induction-current amplification, providing a means to confine and adiabatically heat a target in a step-wise manner [2]. Laser Schlieren imaging of the SZP indicates that even though the liner’s outer surface becomes Rayleigh Taylor unstable, the liner-target interface remains stable until peak compression. The interface stability is accounted for as a shock-front piston [3]. We have investigated its formation and energy coupling as a function of liner-atomic mass [4]. High-atomic number is preferred, leading to a high-energy-density target plasma with fusion products confined in a magnetic well [5]. Recent SZP experiments, designed to investigate these effects, were conducted at the University of Nevada, Reno and Cornell University, on 1 MA, 100 ns pulsers. Data indicate that the SZP is more stable when a target is present, leading to the production of primary (DD) and secondary neutron yields (DT), of thermonuclear origin, as seen in previous experiments [6]. Design refinements to the SZP consider the use of tailored mass profiles to increase the interface pressure and target acceleration [7]. This talk provides a comprehensive summary of the SZP experimental, theoretical, and computational results.
| 附件: 海報.jpg
Introduction of Lunar Impact Flash and Near-Earth Asteroid Observing Camera on Deep-space 6U Spacecraft EQUULEUS and Star-ALE Artificial Meteor Projects
Prof. Shinsuke Abe / Department of Aerospace Engineering, Nihon University )
<演講公告>2017/7/10(一)14:00綜合大樓2樓48218教室演講
(1) EQUULEUS (EQUilibriUm Lunar-Earth point 6U Spacecraft) will be the world’s smallest spacecraft to explore the Earth-Moon Lagrange2 point (EML2). The spacecraft will be jointly developed by the University of Tokyo and JAXA which will be launched by NASA’s SLS (Space Launch System) EM-1 (Exploration Mission-1) in 2019. The spacecraft will fly to a libration orbit around the EML2 point and demonstrate trajectory control techniques within the Sun-Earth-Moon region. We are developing DELPHINUS (DEtection camera for Lunar impact PHenomena IN 6U Spacecraft), one of the scientific instruments which can observe the Lunar impact flashes and near-Earth asteroids.
http://issl.space.t.u-tokyo.ac.jp/equuleus/en/
(2) Japanese space start-up ALE is developing the technology to deliver on-demand man-made meteors, which could turn the night sky into a blank canvas. We plan to launch its first satellite into orbit in 2018, and present its debut show in early-2019, when that satellite has reached its position. I'll introduce our artificial meteor project and EQUULEUS.
http://edition.cnn.com/2016/10/23/asia/on-japan-artificial-meteors/
臺灣航太產業的新想像--我對臺灣航太產業的熱情與夢想
廖榮鑫 董事長 ( 漢翔航空公司 )
<專題討論>2017/6/15(四)15:10國際會議廳第二演講室
| 附件: 漢翔廖榮鑫董事長NCKU演講0606-1.pdf
Tabletop Analog Black Holes and Information Loss Paradox
( 陳丕燊 教授 / 臺灣大學物理系 )
<專題討論>2017/5/25(四)14:30綜合大樓2樓48218教室演講
43 years ago, Stephen Hawking combined quantum field theory with Einstein’s theory of general relativity and discovered black hole evaporation. The debate over whether information is really lost during Hawking evaporation has persisted ever since. Almost all the contemporary leading theoretical physicists have participated in this “black hole war”. In quantum mechanics, the probability, or information, must be preserved before and after a physical process. The seeming loss of information as a result of the black hole evaporation therefore implies that general relativity and quantum mechanics, the two pillars of modern physics, may be in conflict. So far the debate remains purely theoretical, since the the resolution of this paradox relies on the knowledge of the end stage of BH evaporation, yet typical BHs in the universe are too young and cold. Earlier this year, Pisin Chen proposed a table top analog BH experiment using plasma mirrors created by ultra intense lasers.He further organized a new international AnaBHEL (Analog Black Hole Evaporation via Lasers) Collaboration that includes institutions from France, Japan, Mainland China, and Taiwan, to carry out the experiment. This seminar will introduce the history and the physics of BH information loss paradox and the concept of the proposed analog BH experiment.
| 附件: 20170525 陳丕燊教授.pdf