FoSS: ISHW2024
Jump to navigation
Jump to search
The 1st meeting of the Forum of Small Stellarators (1st Uncoordinated Working Group Meeting) took place as a satellite meeting to the 24th ISHW in Hiroshima, Japan on 12 September, 2024.
Agenda
- Welcome and introduction
- ~ 1.5 hours for group introduction presentations. These should be 2-3 slide, <5 minute presentations that provide a brief project overview and any particular strategies to being relevant although small. Each will be followed by 5 minutes of questions / discussion.
- STAR_Lite, Hampton University
- Polaris, École Polytechnique Fédérale de Lausanne
- CSX, Columbia University
- ETOS, University of Wisconsin-Madison
- TJ-K, Universität Stuttgart
- ALPES, Technische Universität Graz
- University of Science and Technology of China
- EPOS, Max-Planck-Institut für Plasmaphysik, Garching
- HU-Heliac, Hiroshima University
- MUSE, Princeton Plasma Physics Laboratory
- Renaissance Fusion
- Heliotron-DR, Kyoto University
- ~ 30 minutes for a coffee break. Opportunity for continuing discussions and engineering questions that are not of general interest.
- ~ 1 hour for brainstorming small stellarator physics investigations and possible joint experiments.
Discussion
training
- training students is a very important and common motivation
- as part of coursework, project management and teamwork can also be trained
- with so many small devices, we should consider collaboration as an important aspect of training
- interest in an arduino-mentality stellarator kit (proposed by F. Volpe)
- standardize a kit to make startup easy, but allow for flexibility
- would be good for exporting stellarators to places with a limited budget, engineering groups without the physics support
- related motivation: outreach
- can we develop some interesting experiments/experiences ?
- moving coils around ? moving a permanent magnet around ?
- something like RGDX at PPPL ?
- web-browser-based control system, providing an experiment remotely
- if also standardized, could have a common web interface for multiple devices (proposed by Y. Suzuki)
- suggest a workshop or bootcamp for development of the interface
- any workshop by the Forum should probably have a strong education aspect
configuration design / physics investigations
- small devices are test bed for integrated design, single-stage optimization
- configuration exploration ? QA, QH, QP, QI, tokamak, RFP ?
- benefits of some good configurations are not trivial to demonstrate at small size when collisionally dominated
- can look at electrons at low pressure, demonstrate drift effects
- turbulence studies, zonal flows
- don't need a big machine, just a big gradient. Columbia had a 10cm linear device doing ITG studies. They had the advantage of open field lines. What are stellarator options to create a large gradient ?
- see validation work at TJ-K. also turbulence work at TORPEX.
- small devices are often studying interchange turbulence. interactions of interchange with energetic particles could be interesting.
- also should look at validation of fluid turbulence codes
- fast particle transport, if can inject dimensionally correct electrons ?
- validate neoclassical flow damping
- explore boundaries of MHD stability
- what is the value of long discharges in small devices ?
- the renormalization parameter in ISS04 hides the physics of deviation from the trend. a greater variety of devices in the database, even at lower performance, could provide this missing information.
- small devices are challenged by background neutral gas. can we make this an advantage ? some sort of plasma-neutral interaction study ? atomic physics ?
- but we don't need a stellarator to study the atom
diagnostics
- variety of diagnostics already being used on small stellarators, some of which are also suitable for fusion plasmas
- field line mapping common to all devices
- probe access is particularly good on small devices
- spectrometers
- magnetic diagnostics
- imaging
- what is the typical budget for diagnostics ?
- wide range, but often zero. they are secondary to an operating device
- consider shared diagnostics ?
- we are happy to get old diagnostics from other machines !
- sharing diagnostics often comes with a lot of paperwork. its not easy to share a fast camera or oscilloscope. but sharing a probe head is easy.
- you need a human to operate diagnostics. it is a natural area for people exchange
- simplest way to get started is to share information. start with sharing how to make diagnostics and how to analyze.
- Forum activity could be to create diagnostic kits. include information, part list, instructions for assembly, tools for analysis. then share people for expertise.
- what is used for data management at small devices ? MDSplus ?
- often use custom format, manual data management
- may be an area for collaboration. standardized data access would facilitate cross-machine comparisons
plasma generation
- can be expensive, but often determines physics capability of device
- radio frequency: can be used for microwave studies, mode conversion, current drive, generation of high-energy electrons ?
- helicon
- electric discharge ?
- MUSE puts a tesla coil outside the vessel, a fun method for outreach physics experiments with a glass vessel
- consider non-neutral plasma, easy to generate