UMD Plasma Seminar

Plasma Physics Seminar

Spring 2025 Schedule

January 29th, Wed. 3:30PM ERF 1207, Large Conference Room	Open
February 5th, Wed. 3:30PM ERF 1207, Large Conference Room	Open
February 12th, Wed. 3:30PM ERF 1207, Large Conference Room	Open
February 19th, Wed. 3:30PM ERF 1207, Large Conference Room	Open
February 27th, Thu. 2:00PM ERF 1207, Large Conference Room SPECIAL DATE AND TIME	Darren Garnier, OpenStar OpenStar Technologies: Developing the Levitated Dipole concept for fusion The levitated dipole fusion concept was proposed by Akira Hasegawa after observing Voyager 2's encounter with Uranus in 1986. Those observations confirmed that planetary magnetospheres have centrally-peaked density and pressure profiles that form naturally from turbulence driven by the solar wind. This remarkable property leads to several advantages of dipoles as fusion devices. Experiments at the Levitated Dipole Experiment (LDX), a joint Columbia/MIT project), showed over a decade ago that such profiles could be demonstrated in laboratory plasmas. Now, OpenStar Technologies, a fusion energy startup spun out of the high-temperature superconducting magnet group of Robinson Research Institute in Wellington New Zealand, is reviving the concept. The OpenStar team has constructed and are currently testing their first dipole, "Junior" with first plasma recently achieved. This LDX-scale device is designed to demonstrate much of the magnet technology required for dipole reactors and reproduce the results from LDX. The next generation machine, "Tahi", has goal of placing the dipole on the Lawson criterion curve of nT-tau, and demonstrating the theoretically decoupled nature of the energy and particle transport within a dipole confined plasma. This seminar will give an introduction to dipole confinement physics, previous experimental results, current operations on Junior, and requirements and initial designs for Tahi.
March 5th, Wed. 3:30PM ERF 1207, Large Conference Room	Open
March 12th, Wed. 3:30PM ERF 1207, Large Conference Room	Open
March 19th, Wed. 3:30PM ERF 1207, Large Conference Room	Spring Break
March 26th, Wed. 3:30PM ERF 1207, Large Conference Room	Abril Sahade, GSFC
April 2nd, Wed. 3:30PM ERF 1207, Large Conference Room	Open
April 9th, Wed. 3:30PM ERF 1207, Large Conference Room	Open
April 16th, Wed. 3:30PM ERF 1207, Large Conference Room	Will Fox, University of Maryland
April 23rd, Wed. 3:30PM ERF 1207, Large Conference Room	Misha Padidar, Flatiron Institute
April 30th, Wed. 3:30PM ERF 1207, Large Conference Room	Open
May 7th, Wed. 3:30PM ERF 1207, Large Conference Room	Open
May 14th, Wed. 3:30PM ERF 1207, Large Conference Room	Open
May 21st, Wed. 3:30PM ERF 1207, Large Conference Room	Soumitro Banerjee, Institute of Science Education & Research Is our Sun going through a bifurcation? Astronomers have noticed that old sun-like stars rotate slower and have reduced magnetic activity than younger stars. The mechanism of magnetic braking of stars is well known, but it is a very slow process. Observational data indicate that there must be another mechanism that becomes active around the middle of a star's life, which renders the magnetic braking mechanism ineffective. There are indications that our Sun, at the age of 4.6 billion years, is now undergoing that `stellar mid-life crisis' because the 11-year solar activity cycle is exhibiting intermittent cycles of dormancy. Using a stochastic delay differential equation model of the mean magnetic field generation process in stars, we show that the phenomenon is caused by the existence of two attractors. As the sun ages, the system can come close to a saddle-node bifurcation point, where the periodic orbit representing the normal magnetic activity coexists with an equilibrium point representing a magnetically dormant state. When the two attractors are sufficiently close to each other, the system noise can intermittently knock the state from the periodic orbit to the equilibrium point and vice versa. These two solutions are possibly involved in the observed bimodal distribution of magnetic cycles in the Sun. On that basis, we argue that the Sun is right now undergoing a bifurcation that will eventually lead to the transition from a magnetically active to an inactive state.

Contact Information: Marc Swisdak or Ian Abel