January 20th, 2021

ICRF coupling in nonaxisymmetric fusion plasmas, by Guillermo Suarez Lopez

Abstract:  Ion cyclotron range of frequencies (ICRF) antennas will be installed in ITER and are also under consideration for DEMO as one of the main auxiliary heating and current-drive systems. ICRF waves are, however, evanescent in low-density plasmas, characteristic of the edge of fusion experimental reactors, but propagate beyond certain density. The coupling of these waves from the evanescent edge to the propagative core is well understood in axisymmetric plasma conditions, i.e., when the coupling region can be assumed homogeneous in poloidal and toroidal directions. However, the coupling of such waves under non-axisymmetric plasma geometries has rarely been systematically studied. Far from odd these non-axisymmetric configurations will be commonplace in fusion demonstration reactors and commercial power plants. For instance, a fusion power plant must operate in a high-confinement regime compatible with power exhaust. One candidate for the plasma scenario is the ELM-free H-mode, where toroidal symmetry is purposely broken to mitigate and even suppress edge localized modes (ELMs). To this effect, magnetic perturbation (MP) fields are applied, which induce a field-aligned plasma kink- response that breaks the usual tokamak toroidal symmetry. Likewise, Stellarators operate, by design, under non-axisymmetric geometry. In these devices, gas puff is also routinely used to improve the coupling conditions for ICRF antennas, in which a neutral cloud is non- axisymmetrically ionized at the edge, endowing the ICRF coupling region with 3D geometry. In this talk, Guillermo will present experimental and numerical results of the effect of non- axisymmetric plasma configurations on the coupling performance of ICRF waves, and prospectives for ITER. Throughout his PhD, he participated in many experiments on the ASDEX Upgrade tokamak, where the MP system was used to systematically study these effects. He compared the obtained measurements against analytical and experimental scaling. Info:  https://fusionep-talks.egyplasma.com/

Join the talk via the Zoom link fusion.yt/af on 20/01/2021 at 16:00 (CET). Password 73852EAF

December 14th, 2020

How to make a plasma behave, by Yashika Ghai

Abstract:  The next big step in fusion research is to create a steady-state hot plasma having temperatures an order of magnitude greater than the core of sun. One way to heat the plasma is by injecting a beam of high-energy neutral particles in the magnetically confined fusion device. As fusion reactions start, the energetic alpha particles are created as a byproduct that help keep the plasma hot for long. However, these energetic particles may also interact with various wave modes in the plasma, exchange energy with them and drive them unstable. The instabilities may lead to high heat fluxes of fast ions on the walls of the vacuum chamber, causing inefficient plasma heating as well as damage to the reactor walls. This talk will be based on explaining the physics of plasma instabilities in fusion devices that arise due to resonant interactions between energetic particles and plasma Alfven waves. Theoretical models for studying energetic particle driven instabilities and ways of mitigating them will be discussed. Info:  https://fusionep-talks.egyplasma.com/

Join the talk via the Zoom link fusion.yt/ae on 14/12/2020 at 16:00 Hrs (CET).

December 9th, 2020

The TOMAS device, a good start of your fusion career, by Andrei Goriaev (FUSION-EP 2014)

Abstract:  The TOMAS (TOroidal MAgnetized System) device, located in Forschungszentrum Jülich, has been significantly upgraded to enable development of various wall conditioning techniques and to complement plasma-wall interaction research in tokamaks and stellarators. The toroidal magnetic field can reach its maximum of 125 mT on axis. The EC system is operated at 2.45 GHz with up to 6 kW forward power. The IC system can couple up to 6 kW in the frequency range of 10 - 50 MHz. The direct current glow discharge system is based on a graphite anode with the maximum voltage of 1.5 kV and current of 6 A. A load-lock system with a vertical manipulator allows exposure of material samples. A number of diagnostics have been installed: single- and triple-pin Langmuir probes for radial plasma profiles, a Time-of-Flight Neutral Particle Analyzer capable of detecting neutrals in the energy range of 10 - 1000 eV, a Quadrupole Mass Spectrometer and video systems for plasma imaging. Besides the recent upgrades there are a lot of opportunities for further upgrades and improvements to the existing components. The device is suitable for tests of new concepts in plasma production systems and development of specific diagnostics for EC/IC plasma studies in toroidal magnetic field configuration. TOMAS being the "hands-on" machine has become an excellent training ground for students and young researchers to obtain necessary skills and experience in experimental physics. Info:  https://fusionep-talks.egyplasma.com/

Join the talk via the Zoom link fusion.yt/ad on 9/12/2020 at 17:00 Hrs (CET).

November 30th, 2020

Kinetic models of the fusion plasma edge, by Dr. David Tskhakaya

Abstract:  This masterclass will give a kinetic view on plasma edge dynamics, which significantly differs from well accepted fluid pictures. Dr. Tskhakaya will describe different numerical tools used for plasma edge study and consider examples of application of such tools - Particle-in Cell models. Plasma edge in fusion devices is a complex plasma layer, where nonlinear interaction between charged and neutral particle, and wall elements are governing plasma and heat exhaust. The optimization of the latter represents one of the main problems in design of future fusion reactors; this determines the importance of plasma edge study. Info:  https://fusionep-talks.egyplasma.com/

Join the talk via the Zoom link fusion.yt/ac on 30/11/2020 at 18:00 Hrs (CET).

November 27th, 2020

Stop the runaway electron beam, by Dr. Sundaresan Sridhar

Abstract:  Relativistic runaway electron (RE) beams are one of the main consequences of disruptions and they carry the risk of in-vessel component damage. The prevention and control of the RE are of prime importance. The current strategy for runaway electrons is to avoid their generation by a massive material injection (MMI). If their generation cannot be avoided, a second MMI will be used to mitigate the generated RE beam. But the problem is, a background plasma of MMI impurities is formed which make the second MMI inefficient to mitigate RE beams, as observed in the JET tokamak. This talk aims to understand the physics of interaction between the RE beam and the mitigation MMI in the presence of a cold background plasma.. Info:  https://fusionep-talks.egyplasma.com/

Join the talk via the Zoom link fusion.yt/ab on 27/11/2020 at 16:00 Hrs (CET).

November 18th, 2020

FUSION-EP talks!

Abstract:  Do you want to know how one of the plasma heating methods was developed? And, on the side, learn enough about its underlying physics and technology that you could use it? How about what happened at the same time in the world? Join this talk from someone who participated in this journey for the last 40 years. Info:  https://fusionep-talks.egyplasma.com/

Join the talk via the Zoom link  on 18/11/2020 at 15:00 Hrs (CET).

November 11th, 2020

FUSION-EP talks!

Abstract:  One of the main difficulties to attain economically viable magnetically controlled thermonuclear fusion reactors is the confinement of alpha particles. In toroidally shaped fusion devices with a non-uniform magnetic field, alpha particles with small parallel velocity become trapped between areas of the high field, bouncing between reflection points, that might result in non-zero radial average drifts and their losses. This talk aims to highlight the link between the alpha particle transport and the confining magnetic field with an emphasis on the trapped particle characterization. Info:  https://fusionep-talks.egyplasma.com/

Join the talk via the Zoom link " https://https://zoom.us/j/86117817013 " using the password "761C9723" (without quotes) on 11/11/2020 at 16:00 Hrs (CET).

November 5th, 2020

FUSION-EP talks!

Abstract:  Future fusion reactors will likely be run in a high-confinement mode called H-mode in order to reach the highest plasma temperatures and densities possible. H-mode is characterized primarily by a steep gradient region near the plasma edge called the H-mode pedestal. While the pedestal helps raise fusion parameters in the core, it is also subject to intense instabilities called Edge Localized Modes (ELMs), which will be intolerable in a reactor setting. In this talk, we will cover the basics of why the H-mode pedestal forms and how it interacts with the plasma. Fundamental theoretical and experimental understandings of ELMs will be discussed, as well as advanced options to operate H-mode plasmas in regimes without ELMs, thereby attaining the benefits of H-mode while avoiding the potentially disastrous possibility of melting the reactor wall.. Info:  https://fusionep-talks.egyplasma.com/

Join the talk via the Zoom link " https://https://zoom.us/j/86117817013 " using the password "D980ABB4" (without quotes) on 5/11/2020 at 17:00 Hrs (CET).

October 15th, 2020

FUSION-EP talks!

Abstract:  Measurement of the current distribution in tokamaks is vital for improving plasma confinement and avoiding performance limiting magneto-hydrodynamic (MHD) instabilities. However, directly measuring the current in the plasma core is challenging. Neutral beam injection systems provide external heating and current drive, and a source of neutral atoms which interact with ions and electrons in the plasma. Emission from these neutrals can be measured using spectroscopy. This opens the possibility of localised measurements of key plasma parameters, such as the toroidal current density and the safety factor (q) profile. In this talk, Sam Gibson will discuss the diagnostic techniques used to measure the current profile, how to design and develop experimental spectroscopy diagnostics for a fusion environment, and the important role spectroscopy will play in the success of ITER. Info:  https://fusionep-talks.egyplasma.com/

Join the talk via the Zoom link " https://https://zoom.us/j/82145836365 " using the password "D7F8B3C0" (without quotes) on 15/10/2020 at 16:00 Hrs (CET).

September 14th, 2020

FUSION-EP talks!

Abstract:  As the fusion community makes pace towards commercialization, the balance in research is shifting from an academic-and-fundamental direction to a technology-and-industry-driven orientation. Internationalization, multidisciplinarity and mobility are key attributes required from leaders in the nascent fusion industry. For nearly 15 years, the FUSION-EP joint Master degree has delivered a high-level research-oriented education and a well-integrated cultural experience within an international consortium of institutions leading the interdisciplinary field of magnetic fusion. The combined and harmonized teaching and research activities coordinated among eight partner universities in Belgium, Czech Republic, France, Germany and Spain offer a variety of competences in a field of crucial importance to the problem of world energy supply. Besides the ITER International Organization, there are presently twenty-five academic and research associate partners from the EU, China, India, Lebanon, Russia, and Ukraine. Professor van Oost is one of the founders of FUSION-EP. In this talk, he will present the structure, philosophy and future perspectives of this unique graduate programme. Prospective students should note that 15 full scholarships are awarded every year to the top candidates!. Info:  https://fusionep-talks.egyplasma.com/

Join the talk via the Zoom link " https://https://zoom.us/j/82145836365 " using the password "5463067F" (without quotes) on 14/09/2020 at 17:00 Hrs (CET).

September 3rd, 2020

FUSION-EP talks!

Abstract:  The fundamental understanding of the behavior of fusion plasmas is based on sophisticated measurements that allow non-invasive diagnosis of certain parameters. This presentation outlines the path from the need to determine a certain quantity, to a conceptual measurement principle towards an actual implementation on a fusion device, using the example of the LLAMA diagnostic. LLAMA stands for Lyman-Alpha Measurement Apparatus, a multi-channel, bandpass filter pinhole camera system and has been recently installed at DIII-D. It measures the Lyman-Alpha brightness profiles at the plasma edge, enabling the inference of edge neutral density profiles to study sourcing of plasma particles. This opens a previously hardly accessible field of studies with specific importance when scaling towards large scale future fusion devices, where the sourcing from neutrals is expected to be drastically reduced. Info:  https://fusionep-talks.egyplasma.com/

Join the talk via the Zoom link " https://https://zoom.us/j/82145836365 " using the password "CE76265E" (without quotes) on 3/09/2020 at 16:00 Hrs (CET).

July 30, 2020

FUSION-EP talks!

Abstract:  It has been known for at least two decades that, in certain regimes, magnetically confined plasmas such as those within a tokamak or stellarator, may exhibit complex, non-diffusive radial transport that is badly modelled by means of traditional, effective, eddy diffusivities or conductivities. These regimes may become very important in next-step experiments, such as the ITER tokamak currently under construction in Southern France. In this talk, we will discuss some of the reasons for the appearance of complex transport behaviour in these plasmas, their implications for plasma confinement as well as give some hints about how these kind of regimes can be more properly modelled by using fractional transport theory. Comparisons with numerical simulations and, when available, experiments, will be also discussed. Info:  https://fusionep-talks.egyplasma.com/

Join the talk via the Zoom link " https://https://zoom.us/j/82145836365 " using the password "593D9FBA" (without quotes) on 24/07/2020 at 18:00 Hrs (CET).

July 24, 2020

FUSION-EP talks!

Abstract:  The talk will be about disruptions events that can arise in tokamaks producing large heat and electromagnetic loads on the structures surrounding the plasma. The dynamics of these events are complex and 3D simulations are required to understand present experiments and to assist the design and operation of future machines. Disruptions induce wall currents which in turn determine the plasma motion, therefore it is necessary to couple these currents to the plasma in a self-consistent form. In the presentation different methods for such a coupling are explained for 3D MHD codes and examples of 3D MHD simulations of Vertical Displacement Events (VDEs) are also presented. Info:  https://fusionep-talks.egyplasma.com/

Join the talk via the Zoom link " https://https://zoom.us/j/82145836365 " using the password "593D9FBA" (without quotes) on 24/07/2020 at 18:00 Hrs (CET).

July 9, 2020

FUSION-EP talks!

Abstract: Hydrogen is one of the key ingredients for fusion energy. During operations, tokamak walls are under bombardment of highly energetic hydrogen ions, which can penetrate the materials. Knowing the hydrogen content of these plasma-facing materials is crucial for several reasons. First from a safety point of view, the tritium content in the inner-vessel of the tokamak is limited to 700 g. Secondly, tritium penetrating the first wall material could reach the cooling system which must then be purified. Finally, hydrogen can brittle the materials and therefore reduce the lifetime of plasma facing components. The behaviour of hydrogen can be investigated by lab experiments but also simulated with thermokinetic models which is the topic of this talk. We’ll present the finite element code FESTIM developed by CEA and CNRS. A particular focus is made on ITER divertor and tungsten monoblocks and hydrogen retention is estimated in the whole divertor.

Join the talk via the Zoom link " https://https://zoom.us/j/82145836365 " using the password "3DE71F17" (without quotes) on Thursday, 9/07/2020 at 18:00 Hrs (CET).

June 30, 2020

FUSION-EP talks!

Abstract: Successful commercial development of fusion energy will require us to find new ways to license and regulate fusion technology that enables innovative and economically viable designs. Fusion energy will likely have unique safety challenges related to the radioactive tritium used as fuel in most proposed commercial reactors. If we want to develop safe and economically competitive fusion energy, we need to incorporate safety and possible regulatory constraints on fusion technology early in the design process. This talk will discuss the major off-site hazards related to commercial fusion technology, what regulatory tools we can use to demonstrate the safety of fusion technology, and how these regulations could affect the design of future fusion power plan.

Join the talk via the Zoom link " https://https://zoom.us/j/82145836365 " using the password "42C1AFOC" (without quotes) on Tuesday, 30/06/2020 at 18:00 Hrs (CET).

June 23, 2020

FUSION-EP talks!

Abstract: New diagnostics in contemporary fusion devices have minor changes but these changes are crucial, this is where diagnosticians compete. But what if all common approaches are not applicable at some place? What if you have to develop solutions which were never used and nothing similar was used? The place where things go this way is called ITER. In ITER, calibrations, adjustments and agile approach improvements are not possible to make minor changes by hand. This and ITER environment requirements make thousands of criteria to be fulfilled in order to complete the work successfully. The talk will present some features of the Thomson scattering diagnostics and focus on some uncommon and specific aspects that became the case in this Divertor Thomson Scattering diagnostic and on supplementary work that is required in such a machine.

Join the talk via the Zoom link " https://https://zoom.us/j/82145836365 " using the password "D681669A" (without quotes) on Thursday, 23/06/2020 at 18:00 Hrs (CET).

June 18, 2020

FUSION-EP talks!

Abstract: The interior of a fusion power plant will be an extreme radiation environment, outside the realm of humanities experience with radiation sources like fission reactors. The materials that make up these power plants must withstand heavy exposure to high energy neutrons, which damage materials, degrading their properties, and driving the components towards failure. Without the ability to accurately reproduce the expected neutron environment through experimentation or simulation, the first fusion power plants face enormous risk of radiation-induced failure of their key components. In order to improve our ability to predict material performance under fusion neutron irradiation, we need new experimental methods for high-fidelity radiation damage testing. Intermediate energy (10-30 MeV) proton irradiation is an under-utilized irradiation technique that could produce radiation damage with high fidelity to a fusion environment Recently, advances in particle accelerator technology have allowed sources of intermediate energy (10+ MeV) protons to become commercially available at a cost and size appropriate for university labs. This talk will give a high-level overview of our work to demonstrate through simulations, theoretical analysis, and experimentation, that protons could play a pivotal role in predicting fusion material performance, ultimately improving the probability of the success of fusion as a global power source.
Join the talk via the Zoom link " https://zoom.us/j/82145836365 " using the password "76E3B4CC" (without quotes) on Thursday, 18/06/2020 at 18:00 Hrs (CET).

May 28, 2020

FUSION-EP talks!

Vignesh is a scientific machine learning engineer at the UK Atomic Energy Agency and an alumni of the European Master in Fusion Science and Engineering Physics. He uses neural networks as a surrogate for the fluid equations describing the behavior of fusion plasma in JET and MAST-U.
In his FusionEPtalk, Vignesh will introduce the neural network solvers for partial differential equations. These regression models, which provide solutions while preserving most of the underlying physics, are particularly efficient in data-starved physical scenarios. Join the webinar and learn how to use his group's state-of-the-art python package for solving PDEs with artificial neural networks.
Join the talk via the Zoom link " zoom.us/j/82145836365 " using the password "E5F5F02B" (without quotes) on Thursday, 28/05/2020 at 18:00 Hrs (CET).