Document Type

Conference Proceeding

Publication Date


Published In

Current Trends In International Fusion Research: Proceedings Of The 7th Symposium

Series Title

AIP Conference Proceedings


Several new experimental results are reported from plasma merging studies at the Swarthmore Spheromak Experiment (SSX) with relevance to collisionless three-dimensional magnetic reconnection in laboratory and space plasmas. First, recent high-resolution velocity measurements of impurity ions using ion Doppler spectroscopy (IDS) show bi-directional outflow jets at 40 km/s (nearly the Alfven speed). The SSX IDS instrument measures with 1 mu s or better time resolution the width and Doppler shift of the C-III impurity (H plasma) 229.7 nm line to determine the temperature and line-averaged flow velocity during spheromak merging events. High flow speeds are corroborated using an in situ Mach probe. Second, ion heating to nearly 10(6) K is observed after reconnection events in a low-density kinetic regime. Transient electron heating is inferred from bursts on a 4-channel soft x-ray array as well as vacuum ultraviolet spectroscopy. Third, the out-of-plane magnetic field and the in-plane Lorentz force in a reconnection volume both show a quadrupolar structure at the ion inertial scale (c/omega(pi)). Time resolved vector magnetic field measurements on a 3D lattice B(r, t)) enables this measurement. Earlier work at SSX has shown that fori-nation of three-dimensional structure at the ion inertial scale is temporally and spatially correlated with the observation of superthermal, super-Alfvenic ions accelerated along the X-line normal to the local 2D plane of reconnection. Each of these measurements will be related to and compared with similar observations in a solar or space context.

Published By

American Institute Of Physics


E. Panarella and R. Raman


7th Symposium On Current Trends In International Fusion Research

Conference Dates

March 5-9, 2007

Conference Location

Washington, DC


This work is freely available courtesy of the American Institute of Physics.