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Mccabe, M. K.

Publications and source records attributed to Mccabe, M. K..

14 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1990

The structure of the white-light corona and the large-scale solar magnetic field

The large-scale density structure of the white-light solar corona is compared to the organization of the solar magnetic field as identified by the appearance of neutral lines in the photosphere to examine whether any consistent relationship exists between the two. During the period covering Carrington rotations 1717 to 1736 brightness enhancements in the low corona tend to lie over the global neutral sheet identified in the photospheric magnetic field. The brightest of these enhancements are associated with neutral lines throguh active regions. These associations are not 1-1, but do hold both in stable and evolving conditions of the corona. A significant number of long-lived neutral lines is found, including filaments seen in H-alpha, for which there are not coronal enhancements.

Sime, D. G.↗
NASA NTRS1985

H-alpha manifestation of an energetic limb flare, June 21, 1980

H-alpha observations of a limb flare, which were associated with exceptional gamma-ray and hard X-ray emission, are presented and discussed. The good spatial and temporal resolution of the H-alpha data allow investigation of the detailed structure of the elevated flare loops and the intensity variations of the loops, footpoints and surrounding chromosphere during each phase of the flare event. A delay time of about 12 s was found between at least one of the hard X-ray (28-485 keV) peaks and corresponding H-alpha intensity maximum at a loop footpoint. A comparison is made between this event and another well-observed limb flare with many similar characteristics, to seek evidence for the large difference in their levels of energy release.

Mccabe, M. K.↗
NASA NTRS1984

The corona near the time of the 1983 June 11 total solar eclipse

Observations are presented of the corona during the June 11, 1983 total solar eclipse, together with preliminary results of a coordinated observing program conducted to investigate the relationship between the corona and the lower parts of the solar atmosphere. Synoptic observations of the white light corona and disk in H-alpha are compared with the eclipse image, together with the inferred longitudinal component of the photospheric magnetic field measured using the magnetically sensitive Fe line at 6303 A. Using these data, an interpretation of the global three-dimensional coronal structure is attempted; showing that the eclipse image contains bright features which are far from the plane of the sky, and that it is dominated by streamers over polar filament neutral lines.

Sime, D. G.↗
NASA NTRS1984

Radio and visible-light observations of a coronal arcade transient

Simultaneous visible-light and radio observations of a coronal transient that occurred on April 9, 1980 are discussed. Visible-light observations of the transient and the associated erupting prominence were available from the Coronagraph/Polarimeter carried aboard SMM, the P78-1 coronagraph, and from the Haleakala Observatory. Radio observations of the related type III-II-IV bursts were available from the Clark Lake and Culgoora Observatories. The transient was extremely complex; it is suggested that an entire coronal arcade rather than just a single loop participated in the event. Type III burst sources observed at the beginning of the event were located along a nearby streamer, which was not disrupted, but was displaced by the outmoving loops. The type II burst showed large tangential motion, but, unlike such sources usually do, it had no related herringbone structure. A moving type IV burst source can be associated with the most dense feature of the white-light transient.

Gergely, T. E.↗
NASA NTRS1984

Progress in the study of homologous flares on the sun. II

Studies of groups of homologous flares in active regions in 1980 were performed using a variety of space and ground-based instruments. The properties of three of the groups are described and combined to form a possible sequence of events.

Woodgate, B. E.↗
NASA NTRS1984

Homologous flares and the evolution of NOAA Active Region 2372

A detailed record of the evolution of NOAA Active Region 2372 has been compiled by the FBS Homology Study Group. It was one of the most prolific flare-producing regions observed by SMM. The flares occurred in distinct stages which corresponded to particular evolutionary phases in the development of the active region magnetic field. By comparison with a similar but less productive active region, it is found that the activity seems to be related to the magnetic complexity of the region and the amount of shear in the field. Further, the soft X-ray emission in the quiescent active region is related to its flare rate. Within the broader definition of homology adopted, there was a degree of homology between the events within each stage of evolution of AR2372.

Strong, K. T.↗
NASA NTRS1982

Identification of Fe I lines in the ultraviolet solar spectrum

High-resolution ultraviolet echelle spectrograms of the sun obtained from a rocket-borne spectrograph have been used for the identification of Fe I absorption lines in the wavelength range 1770-2020 A. Wavelength measurements, with a precision of about 15 mA, are tabulated for 425 Fe I features, along with available laboratory wavelenghs or predicted wavelengths calculated from atomic energy level data. The classification system of Moore has been extended to include possible additional multiplets with 126 newly classified lines; 234 unclassified lines were observed and identified with laboratory Fe I spectra

Mccabe, M. K.↗
NASA NTRS1981

The He I 10,830 A chromosphere and filament associated structures

Full disk, He I 10,830 A solar spectroheliograms have been generated using the Haleakala Stokes polarimeter-spectrometer. The spectroheliograms, with spatial resolution of 10 x 16 arcsec and wavelength bandpass of 0.53 A, were developed for the detection of coronal holes, and have been compared with nearly simultaneous H-alpha and Ca K filtergrams. Areas of reduced helium absorption have been noted in the neighborhood of filaments and neutral zones in the longitudinal solar magnetic field. The existence of these helium lanes is discussed in terms of their relationship to H-alpha filament channels or to the coronal cavities which surround prominences.

Mccabe, M. K.↗
NASA NTRS1974

Observations of coronal disturbances from 1 to 9 solar radii. I - First event of 1973 January 11

H alpha, white-light and radio observations of a coronal disturbance on Jan. 11, 1973, commencing at about 0036 hr UT show that a piston-driven shock wave propagated outward through the corona to heights of at least 9 solar radii. Probably most of the expelled coronal gas originated in a coronal enhancement in the lower corona. An estimate of the kinetic energy and the mass of the expelled gas is obtained which is compatible with observations of piston-driven shock waves near the earth. Shock-wave parameters are evaluated, and a model of the disturbance is outlined.

Stewart, R. T.↗
NASA NTRS1973

Spatial relationship between 5303-A and H alpha components of a loop prominence system.

There are remarkable similarities in the structure of loop prominences when observed in H alpha and coronal lines, although the lines arise from extremely different excitation conditions. This leads to the consideration of a multicomponent model, where different emission lines come from different elements of the structure. The late phases of a large west limb loop prominence system followed by a surge were recorded at Haleakala Observatory on March 6, 1970. Simultaneous filtergrams in H alpha and 5303-A were obtained, together with spectra at three heights in the prominence over the range from 3850 to 5950 A. The positions of bright knots of emission as seen in the green line are compared with associated H alpha knots. With these relative positions determined, the filtergrams are superimposed to demonstrate the two-dimensional spatial relationship between H alpha and 5303-A structures. The results support a model of cool loops within a closely associated hot-loop system.

Mccabe, M. K.↗
NASA NTRS1971

Mass motions in a flare spray

High velocity H alpha ejections in association with important solar flare on 12 March 1969, suggesting mass motions control by gravitational field

Mccabe, M. K.↗