Coronal Density Estimates from the Spartan 201 White Light Coronagraph Experiment

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Session 8 -- Solar Observations and Instrumentation
Display presentation, Wednesday, January 12, 9:30-6:45, Salons I/II Room (Crystal Gateway)

[8.02] Coronal Density Estimates from the Spartan 201 White Light Coronagraph Experiment

M. Guhathakurta (USRA) and R. R. Fisher (NASA) (GSFC, Greenbelt, MD 20771)

A white light coronagraph was launched into orbit aboard the space shuttle OV 103 (Discovery) on 7 April 1993. This device was one of two instruments included in the SPARTAN 201-1 payload, a completely autonomous sub-satellite deployed from the shuttle for a period of about 47 hours. During this period of deployment data were collected by the white light coronagraph (WLC) and the SAO-supplied Ultraviolet Coronagraph (UVC) for investigations of the density, temperature, mass and bulk velocity distributions found in large scale coronal structures.

The WLC system is an externally occulted coronagraph system which incorporates a rotating half-wave plate polarimeter, and the image data is used to infer the brightness, the polarized brightness and degree of polarization of the white light emission from the solar corona. These data are in turn used to infer estimates of the K- and F-coronal brightness and density distributions.

Four targets were selected for the investigation of the corona as seen in the largest spatial scales. A closed magnetic region was observed over the SE limb of the sun at latitude of 50S, considerably distant from any known magnetic active region. A coronal hole region was selected as the second target, located on the front of the sun toward the earth at a latitude of -90 degrees. Considerable activity was available for observation at the west limb of the sun, and a variety of pointings were made over the magnetic active regions seen just south of the equator. Finally, a relatively quiet region in the NW quadrant of the limb was used as a calibration target.

We shall present preliminary results of the electron density estimate in the coronal streamer and hole region and describe the methods employed.

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