Abstract
The effect of weak detrapping of magnetically trapped particles on low-frequency, trapped-particle modes in sheared magnetic configurations is considered; such detrapping can be imposed by oscillation of the magnetic configuration, e.g., by major-radius compression. Detrapping has a dynamical effect analogous to collisions. In particular, it is shown that trapped-particle instabilities in tokamaks can be dynamically stabilized by weak oscillation of the aspect ratio with frequency Ω and relative amplitude λ, thus imitating ion collisions with ion detrapping. In the intermediate regime of the collisional trappedparticle instability, where νi/e≪ω∼ε1/2ω*≪νe/ε, stabilization is found if ω≪Ω<λνe/ε, where ε = r/R. The stabilizing effect (surprisingly of order λ) arises from oscillation of the field strength near its maximum, where detrapping occurs. These results are for simple models of the geometry.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
