Robust Control of Resistive Wall Modes in Tokamak Plasmas Using Mu-Synthesis
نویسندگان
چکیده
Abstract: In this work, μ-synthesis is employed to stabilize a model of the resistive wall mode (RWM) instability in the DIII-D tokamak. The GA/Far-Tech DIII-D RWM model is used to derive a linear state space representation of the mode dynamics. The key term in the model characterizing the magnitude of the instability is the time-varying uncertain parameter cpp, which is related to the RWM growth rate γ . Taking advantage of the structure of the state matrices, the model is reformulated into a robust control framework, with the growth rate of the RWM modeled as an uncertain parameter. A robust controller that stabilizes the system for a range of practical growth rates is proposed and tested through simulations.
منابع مشابه
Interaction of scrape-off layer currents with magnetohydrodynamical instabilities in tokamak plasmas
A simple theoretical model is developed which describes how current eddies are excited in the scrape-off layer SOL of a large-aspect-ratio, low, circular cross-section tokamak by time-varying magnetohydrodynamical instabilities originating from within the plasma. This model is used to study the interaction of SOL currents with tearing modes and resistive wall modes in a typical tokamak plasma. ...
متن کاملExternally Induced Rotation of the Resistive Wall Modes in RFX-mod
Introduction During the last years, significant progress was made in the control of resistive wall modes (RWMs) in reversed field pinches (RFPs). It was demonstrated on several different devices that static current driven RWMs can be completely suppressed and controlled [1,2]. It is well known that also tokamak advanced scenarios suffer from RWM instabilities. The RWM in a tokamak is typically ...
متن کاملEX/P9-5 Comprehensive Control of Resistive Wall Modes in DIII-D Advanced Tokamak Plasmas
The resistive wall mode (RWM) and neoclassical tearing mode (NTM) have been simultaneously suppressed in the DIII-D for durations over 2 seconds at beta values 20% above the no-wall limit with modest electron cyclotron current drive (ECCD) and low plasma rotation. The critical plasma rotation was significantly lower than reported at the IAEA FEC in 2006. However, even in this stabilized regime,...
متن کاملTheory of the scrape-off layer width in inner-wall limited tokamak plasmas
We develop a predictive theory applicable to the scrape-off layer (SOL) of inner-wall limited plasmas. Using the non-linear flattening of the pressure profile as a saturation mechanism for resistive ballooning modes, we are able to demonstrate and quantify the increase of the SOL width with plasma size, connection length, plasma β, and collisionality. Individual aspects of the theory, such as s...
متن کاملStability of the resistive wall mode in HBT-EP plasmas
A relatively simple model of the resistive wall mode RWM is derived for a large aspect ratio, low , circular cross section, tokamak plasma, surrounded by a concentric, thin, uniform resistive wall. The model employs uniform toroidal plasma rotation, and includes the following realistic edge dissipation mechanisms: dissipation due to charge-exchange with cold neutrals, and dissipation due to neo...
متن کامل