ISSN:
1573-093X
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract We describe an ‘electrograph’ instrument designed for measurement of macroscopic electric fields in solar plasmas, using the polarization dependence of line width in Stark-broadened hydrogen Paschen emission lines. Observations of quiescent prominences and limb chromosphere with our electrograph at the NSO/Sac Peak Evans Coronal Facility provide upper limits of 5–10 V cm−1 for transverse macroscopic electric fields in these structures, averaged over an area of about 5 × 7 arc sec. Random thermal motions of hydrogen ions across magnetic field lines generate a quasi-static electric field, which should be distinguishable from pressure broadening in the intensely magnetized chromosphere over a sunspot, given an electrograph sensitivity a factor 2–3 better than that achieved here. Future electrograph measurements of limb flares, post-flare loops and eruptive prominences, even at 5 V cm−1 sensitivity, could provide a useful new test of reconnection and discharge effects in such dynamic structures.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00146705
