Energetic-electron-driven instability in the helically symmetric experiment.
نویسندگان
چکیده
Energetic electrons generated by electron cyclotron resonance heating are observed to drive instabilities in the quasihelically symmetric stellarator device. The coherent, global fluctuations peak in the plasma core and are measured in the frequency range of 20-120 kHz. Mode propagation is in the diamagnetic drift direction of the driving species. When quasihelical symmetry is broken, the mode is no longer observed. Experimental observations indicate that the unstable mode is acoustic rather than Alfvénic.
منابع مشابه
Dissipative trapped-electron instability in quasi-helically symmetric stellarators
The linear electrostatic dissipative trapped-electron mode (DTEM) is investigated in a quasihelically symmetric (QHS) stellarator and a configuration whose symmetry is spoiled by the addition of Mirror contribution to the magnetic spectrum. The effect of the trapped electrons are accounted for using the drift kinetic equation with an energy-dependent Krook collision operator and an effective co...
متن کاملReduction of Neoclassical Transport and Observation of a Fast Electron Driven Instability with Quasisymmetry in HSX
The Helically Symmetric Experiment (HSX) is the first operational quasisymmetric stellarator, with neoclassical transport at low collisionality greatly reduced compared to a conventional stellarator. Experimental differences in the density and temperature profiles are observed between the quasihelically symmetric (QHS) configuration and a configuration with the symmetry intentionally broken. Th...
متن کاملA Finite Element Model for Simulating Flow around a Well with Helically Symmetric Perforations
In a perforated well, fluids enter the wellbore through array of perforation tunnels. These perforations are typically distributed in a helical pattern around the wellbore. Available numerical models to simulate production flow into cased-and-perforated vertical wells have complicated boundary conditions or suffer from high computational costs. This paper presents a simple and at the same time ...
متن کاملFluid description of collisional current filamentation instability of a weakly ionized plasma in the presence of magnetic field
In this paper, the collisional filamentation instability of an electron beam-weakly magnetized and ionized plasma has been investigated in the presence of background plasma, using the fluid description. By describing the equilibrium configuration in the presence of binary collision terms between charged and neutral particles and using the local approximation method, the dispersion relation (DR)...
متن کاملNon-ideal MHD ballooning modes in three-dimensional configurations
A linear stability theory of non-ideal MHD ballooning modes is investigated using a two fluid model for arbitrary three-dimensional electron-ion plasmas. Resistive-inertia ballooning mode (RIBM) eigenvalues and eigenfunctions are calculated for a variety of equilibria including axisymmetric shifted circular geometry (s − α model) and configurations of interest to the Helically Symmetric Stellar...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Physical review letters
دوره 103 2 شماره
صفحات -
تاریخ انتشار 2009