HEPP-Seminar 2021

tba / A fast neural network surrogate for the VMEC MHD equilibrium code

HEPP Seminar

HEPP-Workshop "Improved Reading"

14.01.2021, 13:00-15:00; between 15.01.2021 and 21.02.2021: individual appointment; 22.02.2021, 13:00-15:00 [mehr]

tba

HEPP Seminar

Influence of the 3D main chamber geometry on SOL plasma parameters of ASDEX UPGRADE

HEPP Colloquium
Simulated plasma backgrounds for impurity migration schemes in Tokamaks focus mainly on divertor solutions and match experimental up- and downstream profiles in a poloidal cross section. This assumes toroidally symmetric plasma solutions in both the divertor and upstream in the main chamber. While the divertor is essentially toroidally symmetric, the main chamber often includes features like poloidal limiters and probes that can break this symmetry. Taking these toroidal asymmetries into account impacts ionization source distributions, plasma profiles and flow patterns. This has an influence on particle fluxes to and from wall elements and changes the redistribution of impurities within the vessel.For this talk EMC3-EIRENE was used to simulate two plasma backgrounds. One plasma background assuming a toroidally symmetric vessel wall and one background featuring 3D poloidal limiters and a midplane deposition probe. Differences in both plasma solutions and resulting changes in the redistribution of impurities will be presented. [mehr]

Can we make the DEMO NBI more efficient with a beam-driven plasma neutraliser?

HEPP Colloquium
The energy efficiency of the neutral beam injectors (NBI) on ITER is currently limited by the gas neutralisation. In order to make the cost of the electricity coming from fusion competitive, the NBI energy efficiency of future magnetic-confinement fusion machines, such as DEMO or a fusion power plant, must be increased and the neutraliser is the component where the highest improvement is possible. The beam-driven plasma neutraliser (BDPN) is one of the technologies that have been considered to overcome the limitations of the gas neutraliser: if the neutraliser gas is sufficiently ionised, collisions with ions and electrons enhance the stripping of the negative beam ions, thus increasing the neutralisation yield. The plasma inside the chamber is created through the gas ionisation by the negative ion beam itself and confined by means of a magnetic cusp field generated with permanent magnets, avoiding the complexity of having an external power source. The original zero-dimensional model of Surrey and Holmes, describing the underlying physics of the BDPN, has been revisited and modified, in particular by introducing the computation of the plasma species composition which allows to consider the plasma loss due to electron-ion dissociative recombination. A neutralisation yield of 75 % is predicted with respect to the value of ~ 55 % foreseen for the ITER NBI’s gas neutraliser. Such a prediction has to be experimentally benchmarked, but at the moment no NBI beamline exists whose parameters are in the relevant range for DEMO. After discussing the possibility of testing the BDPN by installing one on an existing NBI beamline, I will argue that the most suitable proof-of-principle experiment is a dedicated chamber in which the plasma is not created by the fast electrons stripped from the beam ions, but by electrons emitted from biased filaments with the same energy and current. [mehr]

Closing the gap between simulations and experiment with GRILLIX

HEPP Colloquium
Understanding and predicting the scrape-off layer and divertor plasma is a crucial step for building confidence in fusion reactor designs. Building a predictive model is challenging, however, since the scrape-off layer and divertor plasma is challenging to model. The dynamics in these regions is governed by a complex interaction of effects, including strong magnetic shaping and the “sheath” plasma-surface interaction.In this talk, I will discuss how the GRILLIX fluid turbulence code was extended to treat realistic experimental magnetic geometries. I will also discuss two validations which were made using the extended version of GRILLIX — on the TORPEX and TCV devices at the Swiss Plasma Centre. The agreement found with TCV shows that the GRILLIX code can closely predict the absolute magnitude and shape of many outboard midplane, divertor volume and target measurements. These results are particularly remarkable because they come from “hands-off” GRILLIX simulations — the only free “knob” is the density source rate since the neutral ionisation is not yet included. These simulations therefore represent a significant step towards building predictive capability. Finally, I will discuss the potential applications of the validated code — including a promising ongoing project regarding predicting the turbulence levels within advanced divertor concepts. [mehr]

The Role of the Tertiary Instability for the Collisionless Dimits Shift

HEPP Colloquium
As a result of shearing zonal flows, many plasma systems exhibit basically no transport until well above the linear marginal stability threshold. This effective upshift of the critical gradient is known as the Dimits shift, a detailed description of which is still lacking. To remedy this, in this work the role of the tertiary instability, within and beyond the Dimits shift regime of different collisionless systems, is investigated. Through tertiary linear stability analysis and nonlinear simulations, both of simple fluid systems and full gyorokinetics as simulated by GENE, it is found that in simple geometries the collisionless Dimits transition corresponds to a linear tertiary transition. An efficient reduced prediction model exploiting this fact is therefore postulated and finally verified. [mehr]

Presentation Skills for Scientists

HEPP Seminar
Presenting your results is part of being a scientist: in your group seminar, on a conference, for your PhD defense or for general public. How can you do this convincingly? [mehr]

Scrape-off Layer Investigations on W7-X via Line Ratio Spectroscopy on a Thermal Helium Beam

HEPP Seminar

tba / Extending the GENE code for improved edge turbulence studies

HEPP Seminar

Good Scientific Practice - HEPP

Seminar
registration via https://event.ipp-hgw.mpg.de/event/39/In public, "good scientific practice" is often connected with cases of plagiarism when it comes to dissertations. However, the important topic covers a substantially wider spectrum of scientific conduct: Dealing with data (including checking, recording, ownership and storage), the publishing process and authorship, responsible supervision, academic cooperation, conflicts of interest and dealing with conflicts. Inappropriate academic behaviour includes inventing or faking data, violating intellectual property (theft of ideas or plagiarism), and sabotaging the research of others. More subtle topics, such as skepticism, critical thinking, reproducibility, handling creativity, the danger of axiomatic assumptions and confirmation bias represent the “heart of good scientific practice”. Every scientists should have a professional understanding of all mentioned topics. [mehr]

HEPP-Workshop "Improved Reading"

13.08.2021, 15:00-17:00; between 16.08.2021 and 09.09.2021: an individual appointment; 10.09.2021, 15:00-17:00Better reading. With system. [mehr]

9. Career Dialogue "Dr. Christian Konz - Patent Attorney, Qualcomm, München"

Career Dialogue
For the Career Dialogue we invite people with different backgrounds who will initially tell about themselves, their career or their networks and will then answer your questions and engage in a dialogue with you. The purpose of the Career Dialogue is to provide insight into different career paths, to bring you in contact with people outside IPP and to enhance our networks in all directions - science, industry, entrepreneurship, science management. [mehr]

Project management for Scientists! (Postdocs)

Career Center Workshop
Manage your Research Projects successfully! Project and Self-Management for Postdocs [mehr]

Basics of Professional Coding Part II (Postdocs, PhDs)

Career Center Workshop
IPP intern coding1. Debugging, LaTeX integration (all) (D. Böckenhoff, G. Fuchert)2. Good Visualisation (all) (G. Fuchert)3. Special libraries (AUG data, W7-X data) (AUG: A. Bock, G. Tardini; W7-X: D. Böckenhoff, K.J. Brunner, G. Fuchert, U. Höfel) [mehr]

Basics of Professional Coding Part III (Postdocs, PhDs)

Career Center Workshop
introduction into the usage of the version control system git and the features of MPCDF gitlab and the usage of the Continuous Integration (CI) features of it. [mehr]

Parallel expansion of a pellet plasmoid

HEPP Seminar

10. Career Dialogue "Dr. Josefine Proll - Assistant Professor in the Department of Applied Physics at Eindhoven University of Technology"

Career Dialogue
For the Career Dialogue we invite people with different backgrounds who will initially tell about themselves, their career or their networks and will then answer your questions and engage in a dialogue with you. The purpose of the Career Dialogue is to provide insight into different career paths, to bring you in contact with people outside IPP and to enhance our networks in all directions - science, industry, entrepreneurship, science management. [mehr]

Advanced HPC workshop (MPCDF)

MPCDF Workshop
introduction into the usage of the version control system git and the features of MPCDF gitlab and the usage of the Continuous Integration (CI) features of it. [mehr]

ECRH during early plasma formation / tba

HEPP Seminar

HEPP-Workshop "Good Scientific Practice"

HEPP Seminar
registration via https://event.ipp-hgw.mpg.de/event/45/In public, "good scientific practice" is often connected with cases of plagiarism when it comes to dissertations. However, the important topic covers a substantially wider spectrum of scientific conduct: Dealing with data (including checking, recording, ownership and storage), the publishing process and authorship, responsible supervision, academic cooperation, conflicts of interest and dealing with conflicts. Inappropriate academic behaviour includes inventing or faking data, violating intellectual property (theft of ideas or plagiarism), and sabotaging the research of others. More subtle topics, such as skepticism, critical thinking, reproducibility, handling creativity, the danger of axiomatic assumptions and confirmation bias represent the “heart of good scientific practice”. Every scientists should have a professional understanding of all mentioned topics. [mehr]
Zur Redakteursansicht