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Erskine, F. T.

Publications and source records attributed to Erskine, F. T..

6 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1984

Microwave, soft and hard X-ray imaging observations of two solar flares

A set of microwave and hard X-ray observations of two flares observed simultaneously with the Very Large Array (VLA) and the Solar Maximum Mission Hard X-ray Imaging Spectrometer (SMM-HXIS) are presented. The LVA was used at 6 cm to map the slowly varying and burst components in three neighboring solar active regions (Boulder Nos. 2522, 2530, and 2519) from approximately 14:00 UT until 01:00 UT on June 24-25, 1980. Six microwave bursts less than 30 sfu were observed, and for the strongest of these, two-dimensional 'snapshot' (10 s) maps with spatial resolution of 5 in. were synthesized. HXIS data show clear interconnections between regions 2522 and 2530. The X-ray observations present a global picture of flaring activity, while the VLA data show the complexity of the small magnetic structures associated with the impulsive phase phenomena. It is seen that energy release did not occur in a single isolated magnetic structure, but over a large area of intermingled loop structures.

Kundu, M. R.↗
NASA NTRS1982

Time variability and structure of quiet sun sources at 6 cm wavelength

Results are presented of a detailed study of quiet sun emitting regions at 6 cm and their correspondence with regions observed at optical wavelengths. The Westerbork Synthesis Radio Telescope was used to obtain a 12-hr synthesis map of a quiet sun region with a resolution of 6 arcsec. Comparison of this map with a Ca(+) K filtergram indicates the features on the 6-cm map to correspond to Ca(+) K chromospheric networks and cells. In addition, about 72% of the magnetic field enhancements observed on photospheric magnetograms coincides with 6-cm emissive regions. Intercomparison of the 12-hr synthesis map, a 4-hr synthesis map and 6-cm fan beam scans along with the Ca(+) K and magnetogram results reveals all of the time-varying 6-cm elements to be located on Ca(+) K networks, and about 40% of them to be coincident with magnetogram enhancements. Lifetimes of the time-varying sources vary from a few minutes to several tens of minutes, and intensity varies by factors of 2 to 7.

Erskine, F. T.↗
NASA NTRS1980

6 cm observations of a solar active region and bursts with approximately 6 arcsec resolution

The paper examines the solar active region located near N04E49, that was mapped at a 6 cm wavelength over a period of 12 hours, employing the Westerbork synthesis radio telescope. Two impulsive radio bursts were recorded during this time, one of which was associated with a chromospheric flare. One-dimensional fan beam scans of the burst sources were synthesized in order to display their time history with regard to intensity, polarization, position and size.

Erskine, F. T.↗
NASA NTRS1978

Interplanetary scintillation at large elongation angles - Response to solar wind density structure

Synoptic interplanetary scintillation (IPS) index measurements at 34.3 MHz were obtained during May-December 1974 by means of the University of Iowa Cocoa Cross radiotelescope on a 'grid' of 150 selected radio sources covering solar elongation angles up to 180 deg. Over 80 of these sources displayed definite IPS, and the solar elongation dependence of the 34.3-MHz IPS index is consistent with the elongation of angle dependence measured at higher frequencies. Large enhancements of the IPS index are found to coincide with solar wind (proton) density increases greater than 10/cu cm. Correlation analysis confirms the IPS response to solar wind density and indicates that the events are due primarily to the corotating solar wind turbulent plasma structures which dominated the interplanetary medium during 1974.

Erskine, F. T.↗
NASA NTRS1976

Interplanetary scintillation observations with the Cocoa Cross radio telescope

Physical and electrical parameters for the 34.3-MHz Cocoa Cross radio telescope are given. The telescope is dedicated to the determination of solar-wind characteristics in and out of the ecliptic plane through measurement of electron-density irregularity structure as determined from IPS (interplanetary scintillation) of natural radio sources. The collecting area (72,000 sq m), angular resolution (0.4 deg EW by 0.6 deg NS), and spatial extent (1.3 km EW by 0.8 km NS) make the telescope well suited for measurements of IPS index and frequency scale for hundreds of weak radio sources without serious confusion effects.

Cronyn, W. M.↗