John Verboncoeur
Associate Dean for Research and Graduate Studies Michigan State University
- East Lansing MI
John Verboncoeur studies computational plasma physics, electromagnetics, beam physics and high field effects,
Media
Biography
Industry Expertise
Areas of Expertise
Accomplishments
Charles K. Birdsall Award, Nuclear and Plasma Sciences Society of the Institute of Electrical and Electronic Engineers
2022
Education
University of California - Berkeley
Ph.D.
Nuclear Engineering
1992
Affiliations
- Senior Member, IEEE
News
Michigan State University's LiDAR Demonstration - John Verboncoeur
Michigan Online online
2019-01-17
In this segment at the North American International Auto Show, John gives a memorable demonstration of how Lidar works to give self-driving cars an idea of what is around them. He also explains some of the initiatives in the self-driving car space that are happening at Michigan State University.
Journal Articles
Field reversal in low pressure, unmagnetized radio frequency capacitively coupled argon plasma discharges
Applied Physics Letters2023
In general, the radio frequency (rf) electric field within a sheath points toward the metal electrode in low pressure, unmagnetized rf electropositive capacitively coupled plasma (CCP) glow discharges. This is due to the large ratio of electron to ion mobility and the formation of an ion sheath. In this work, we studied, using fully kinetic particle-in-cell simulations, a reversed electric field induced by the strong secondary electron emission during the phase of sheath collapse in a high-voltage rf-driven low pressure CCP glow discharge.
Recent advances in multipactor physics and mitigation
High Voltage2023
Recent progress made in the prediction, characterisation, and mitigation of multipactor discharge is reviewed for single‐ and two‐surface geometries. First, an overview of basic concepts including secondary electron emission, electron kinetics under the force law, multipactor susceptibility, and saturation mechanisms is provided, followed by a discussion on multipactor mitigation strategies. These strategies are categorised into two broad areas – mitigation by engineered devices and engineered radio frequency (rf) fields. Each approach is useful in different applications.
Two surface multipactor with non-sinusoidal RF fields
Journal of Applied Physics2023
Two-surface multipactor with a Gaussian-type waveform of rf electric fields is investigated by employing Monte Carlo simulations and 3D electromagnetic particle-in-cell simulations. The effects of the full width at half maximum (FWHM) of the Gaussian profile on multipactor susceptibility and the time dependent dynamics are studied. The threshold peak rf voltage, as well as the threshold time-averaged rf power per unit area for multipactor development, increases with a Gaussian-type electric field compared to that with a sinusoidal electric field.
Effect analysis of spatial discrepancy of secondary emission yield on multipactor formation
Physics of Plasmas2023
Spatial discrepancy of secondary emission yield (SEY) is probably exacerbated by unexpected surface contamination or imperfect surface treatments for SEY suppression, which accordingly provokes increased multipactor risk in microwave devices. In this paper, an improved 2D2V nonstationary statistical modeling for multipactor of parallel plates capable of regarding all electron impacts and electron exchange at the periodic boundaries is developed to investigate the effect of this spatial SEY discrepancy on multipactor formation in microwave devices.
Similarity-based scaling networks for capacitive radio frequency discharge plasmas
AIP Advances2023
We demonstrate similarity-based scaling networks for capacitive radio frequency (RF) plasmas, which extensively correlate discharge characteristics under varied conditions, incorporating the transition from original to similarity states. Based on fully kinetic particle-in-cell simulations, similar RF discharges in argon are demonstrated with three external control parameters (gas pressure, gap distance, and driving frequency) simultaneously tuned. A complete set of scaling pathways regarding fundamental discharge parameters is obtained, from which each plasma state finds its neighboring node with only one control parameter tuned.
