Design and implementation of the plasma control system for the COMPASS tokamak

Design and implementation of the plasma control system Mgr. Filip Janky The COMPASS tokamak was recommissioned in 2007 and it needed new digital controllers for its experimental research. This thesis presents the design and imple- mentation of control of main plasma parameters such as plasma current, plasma position, plasma shape and electron density. Improved plasma current control with resetting set points suppresses overshooting and thus increases the length of the flat top phase. A method for estimating the plasma position, gain tuning for the controller and decreasing latencies and delays to obtain robust position control are presented. Lower delays improve plasma stability and decrease the frequency of disruptions. The plasma shape controller is a feedforward controller with a method to suppress oscillations which are coming from mutual inductance between power supplies controlling plasma horizontal position, plasma shape and plasma current, which all use the same coil. Averaged electron density is corrected in real-time according to the interferometer line of sight and a non-linearity of measurement. Controllers and their improvements described here, played a major role in achiev- ing H-mode scenario and fulfilling the experimental program. Keywords: tokamak, plasma current control, plasma position..

Návrh a implementácia systému kontroly plazmy pre tokamak COMPASS

Návrh a implementácia systému kontroly plazmy Mgr. Filip Janky Tokamak COMPASS po opätovnom uvedení do prevádzky v roku 2007 potre- boval nový digitálny kontrolný systém pre svoj experimentálny výskum. Táto dizertačná práca prezentuje návrh a implementáciu kontroly hlavných parametrov plazmy ako prúd, poloha, tvar a elektrónová hustota. Vylepšená kontrola prúdu plazmy s resetovaním referenčných hodnôt potlačuje oscilácie, zabraňuje prekmitu a tak predlžuje trvanie plazmy. Opísaná metóda na určovanie polohy plazmy, vy- ladenie kontroléru a skrátenie oneskorenia, zvýšila stabilitu polohy plazmy a znížila výskyt dizrupcií. Tvar plazmy je kotrolovaný doprednou väzbou s metódou na potlačovanie oscilácií spôsobených vzájomnou indukčnosťou medzi zdrojmi a tiež tým, že využívajú spoločné vinutie. Priemerná elektrónová hustota je v reálnom čase korigovaná podľa d'lžky trasy vlny interferometru plazmou a nelineárnosťou merania. Prezentované kontroléry a ich vylepšenia zohrali kľúčovú úlohu k dosi- ahnutiu H-módu a naplneniu experimentálneho programu. Klíčová slova: tokamak, kontrola prúdu plazmy, kontrola polohy plazmy, kon- trola tvaru plazmy, kontrola elektrónovej hustoty 1Design and implementation of the plasma control system Mgr. Filip Janky The COMPASS tokamak was recommissioned in 2007 and it needed new digital controllers for its experimental research. This thesis presents the design and imple- mentation of control of main plasma parameters such as plasma current, plasma position, plasma shape and electron density. Improved plasma current control with resetting set points suppresses overshooting and thus increases the length of the flat top phase. A method for estimating the plasma position, gain tuning for the controller and decreasing latencies and delays to obtain robust position control are presented. Lower delays improve plasma stability and decrease the frequency of disruptions. The plasma shape controller is a feedforward controller with a method to suppress oscillations which are coming from mutual inductance between power supplies controlling plasma horizontal position, plasma shape and plasma current, which all use the same coil. Averaged electron density is corrected in real-time according to the interferometer line of sight and a non-linearity of measurement. Controllers and their improvements described here, played a major role in achiev- ing H-mode scenario and fulfilling the experimental program. Keywords: tokamak, plasma current control, plasma position...Matematicko-fyzikální fakultaFaculty of Mathematics and Physic

Basic design considerations for a frequency step-tunable electron cyclotron wave system to suppress NTMs in DEMO

| openaire: EC/H2020/633053/EU//EUROfusionAn Electron Cyclotron Wave (ECW) system will be used in the European DEMO for the stabilization of Neoclassical Tearing Modes (NTMs). In order to avoid movable mirrors in the harsh environment close to the plasma and to simplify the NTM launcher integration, the tuning of the ECW deposition location can be achieved by launching frequency-tunable ECWs from fixed mirrors while the frequency is tuned in discrete steps of 2–3GHz. An overview of the frequency step-tunable ECW system for NTM stabilization is presented. The design considerations are discussed based on the current DEMO baseline parameters and the status of technologies. A simulation of NTM stabilization with an idealized frequency tunable ECW system on an analytical NTM model is shown. The simulation takes into account a realistic tuning speed based on the present technology and considers the current NTM launcher configurations in DEMO. A simple sweeping strategy is adapted for the control of frequency. Various uncertainties, which will affect the feasibility, need to be further investigated.Peer reviewe

Basic design considerations for a frequency step-tunable electron cyclotron wave system to suppress NTMs in DEMO

An Electron Cyclotron Wave (ECW) system will be used in the European DEMO for the stabilization of Neoclassical Tearing Modes (NTMs). In order to avoid movable mirrors in the harsh environment close to the plasma and to simplify the NTM launcher integration, the tuning of the ECW deposition location can be achieved by launching frequency-tunable ECWs from fixed mirrors while the frequency is tuned in discrete steps of 2–3GHz. An overview of the frequency step-tunable ECW system for NTM stabilization is presented. The design considerations are discussed based on the current DEMO baseline parameters and the status of technologies. A simulation of NTM stabilization with an idealized frequency tunable ECW system on an analytical NTM model is shown. The simulation takes into account a realistic tuning speed based on the present technology and considers the current NTM launcher configurations in DEMO. A simple sweeping strategy is adapted for the control of frequency. Various uncertainties, which will affect the feasibility, need to be further investigated

The bacterial quorum sensing peptide iAM373 is a novel inducer of sarcopenia

Sarcopenia-the accelerated loss of muscle mass, strength and function with ageing-represents an important health challenge with reduced quality of life and increased mortality. Gut microbiota has been suggested to contribute to this age-associated muscle wasting but the underlying mechanisms are still unclear. Here, we uncover the quorum sensing peptide iAM373 as a hitherto unknown contributor to sarcopenia

Disruption avoidance strategies for DEMO

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