BEGIN:VCALENDAR VERSION:2.0 CALSCALE:GREGORIAN PRODID:UW-Madison-Physics-Events BEGIN:VEVENT SEQUENCE:1 UID:UW-Physics-Event-8432 DTSTART:20231003T160000Z DTEND:20231003T180000Z DTSTAMP:20260414T031202Z LAST-MODIFIED:20230927T123409Z LOCATION:B343 Sterling SUMMARY:Intermittency in the Dimits Regime of Toroidal Ion Temperature Gradient Driven Turbulence\, Graduate Program Event\, Augustus Azelis \, Department of Physics Graduate Student DESCRIPTION:In toroidal ion temperature gradient (ITG) driven turbulen ce\, it remains a challenge to understand heat flux reduction at and a bove the threshold of linear instability for a range of driving gradie nts called the Dimits regime. A known but unexplained feature of this regime is the observation of temporally intermittent turbulent fluctua tions and resulting transport. Preexisting theory for the Dimits shift successfully attributed heat flux reduction to resonance in mode coup ling\, but this analysis was based on a cumulant-discard method which neglected intermittency and also did not produce any bifurcation demar cating variation in transport with driving gradient above and below th e nonlinear critical threshold. In this work\, weak turbulence closure s are employed to produce dynamical equations for a fourth order cumul ant as well as the heat flux itself. The former predicts conditions un der which intermittent behavior may develop while the latter is a dire ct attempt to model said phenomenon. Preliminary analysis has found st rong cumulant growth near the linear threshold which can be attributed to resonances in triplet correlation times and nonlinear coupling coe fficients. This suggests possible coincidence between the mechanism re sponsible for heat flux suppression and the inherent non-Gaussian tend encies of the Dimits regime. Analytical work is compared against solut ions of the reduced two-field fluid model for toroidal ITG driven turb ulence from the numerical solver Dedalus. URL:https://www.physics.wisc.edu/events/?id=8432 END:VEVENT END:VCALENDAR