Denis St-Onge is a Ph. D. candidate at PPPL. He obtained his B.Sc. at Mount Allison University and his M.Sc. at the University of Alberta.
His research interests include nonlinear phenomena and turbulence in astrophysical and fusion plasmas. He is currently working with Prof. Matthew Kunz on the small-scale dynamo in a turbulent, collisionless plasma, in an effort to explain the observed strengths of magnetic fields in clusters of galaxies. This work focuses on the initialization and sustenance of the dynamo, both of which rely heavily on the plasma physics occuring on ion-Larmor scales.
Previous work includes work on the Dimits shift, a nonlinear upshift in the stability boundary due to zonal-flow production typically encountered in collisionless gyrokinetic simulations of ion-temperature-gradient turbulence. Using simplified models, the roles of the secondary and tertiary instabilities in the Dimits shift have been better elucidated. Additionally, this work yielded simple but accurate estimates of the nonlinear stability threshold.