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Tousey, R.

Publications and source records attributed to Tousey, R..

At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1979

Measurements of spectrally integrated atmospheric transmittance in the O2 Schumann-Runge bands and derived oxygen column densities - 76-102 km

Atmospheric transmittances integrated over wavelength intervals corresponding approximately to the (15-0) through (4-0) Schumann-Runge bands of O2 have been determined from EUV solar spectra (wavelengths between 1768 and 1948 A) photographed at seven altitudes between 102 and 76 km with a rocket-borne spectrograph having a resolution of 0.07 A. The observed transmittances are compared with atmospheric transmittances predicted from three models of the O2 absorption cross section. The predicted transmittances have also been used to derive column densities of atmospheric O2 from the observations. The results are compared with values calculated from the U.S. Standard Atmosphere (1976) and with oxygen column densities determined by Prinz and Brueckner (1977) from EUV solar spectra of the Schumann-Runge continuum (wavelength below 1750 A) and of the H-Lyman alpha line (1216 A) recorded on the same films used in the present research. The comparisons test the utility of the models for studies of atmospheric photochemistry, suggest which models may be best for this purpose, and indicate how the models can be improved.

Longmire, M. S.↗
NASA NTRS1979

On the solar coronal lines 1175-1965 A

Sixteen new coronal lines are observed in ATM UV spectra. Identifications, wavelengths, and intensities are presented. Two additional lines observed previously are proposed as transitions within the 3p(3)3d configuration of Fe XI.

Sandlin, G. D.↗
NASA NTRS1978

A survey of coronal holes and their solar wind associations throughout sunspot cycle 20

Space-borne X-ray and XUV observations during the period 1963-74 (corresponding approximately with solar cycle 20) have been used to investigate the relationship between the occurrence and variability of coronal holes and solar activity, i.e., the solar wind. Results indicate that polar holes (prominent at solar minimum) decreased in area as solar activity increased. The equatorial holes were also small during this period and persisted for one or two solar rotations only. Solar wind streams in excess of 500 km/s were associated with coronal holes at less than 40 deg latitude, although solar coronal holes appear to have no associated wind streams at earth.

Broussard, R. M.↗
NASA NTRS1977

Forbidden lines of the solar corona and transition zone - 975-3000 A

Forbidden lines characteristic of plasmas at temperatures of 50,000 to 3 million K are observed in ATM UV spectra. Identifications, accurate wavelengths, ionization classes, intensities, and half-widths are presented. Coronal blends with He II at 1640 A are noted. Variations in nonthermal velocities with limb distance are observed. Doppler shifts in the coronal lines observed on the disk may be related to the solar wind. The coincidence of two lines with F IV(3P-5S) is evidence for atomic fluorine in the sun.

Sandlin, G. D.↗
NASA NTRS1977

Extreme ultraviolet spectroheliograph ATM experiment S082A

The XUV spectroheliograph, Apollo Telescope Mount experiment S082A, is described. The instrument was a slitless Wadsworth grating spectrograph that employed photographic recording. The grating was of 4-m radius, ruled with 3600 grooves/mm. By rotating the grating to positions where the normal was at 255 A or 400 A, the spectral ranges 175-335 A and 320-480 A, respectively, were covered with 2-sec of arc spatial resolution. Close to the normal the resolution reached 2 sec of arc, but at the extreme limit, 630 A, it was 10 sec of arc or worse. The aberrations of the instrument are discussed in detail as are the provisions necessary to maintain optimum imagery and reliability in a space environment. During the mission about 1020 exposures were made covering 171-335 A or 320-630 A.

Tousey, R.↗
NASA NTRS1977

Extreme ultraviolet spectrograph ATM experiment S082B

The extreme-ultraviolet double-dispersion photographic spectrograph for the Apollo Telescope Mount (ATM) experiment S082B on Skylab is described. Novel features were the use of a predisperser grating with a ruling whose spacing varied approximately linearly with distance for the purpose of increasing the instrument speed by reducing the astigmatism and a photoelectric servosystem to stabilize to 1 sec of arc the solar image at various near-limb positions. The 970-3940-A range was covered in two sections with effective resolving power of approximately 30,000 from 1100 A to 1970 A. The spatial resolution was 2 x 60 solar sec of arc. During the Skylab mission 6400 exposures were made with the instrument pointed by an astronaut at selected and recorded solar positions.

Bartoe, J.-D. F.↗
NASA NTRS1977

NRL-ATM extreme ultraviolet solar image TV monitor flown on Skylab

An instrument for recording extreme ultraviolet television images of the sun was flown in the Apollo Telescope Mount on Skylab. Solar radiation in the 171-630 A wavelength range, defined by the transmission band of three thin-film aluminum filters, was focused onto a p-quaterphenyl photon conversion layer by a platinum-coated mirror at normal incidence. The conversion layer was attached to the faceplate of a low light level SEC vidicon. An onboard video monitor enabled the Skylab crews to observe the images in real-time and to identify and follow the development of solar features. Images were also transmitted to the mission control center, where they were used in planning the ATM observing schedule.

Crockett, W. R.↗
NASA NTRS1977

Observing and recording instantaneous images on ATM television monitors

A persistent image-converter device was utilized to make visible to the astronaut solar images that were isolated, instantaneous flashes on the ATM TV monitors. In addition, these instantaneous images, as well as normal TV images, were recorded with a Polaroid SX-70 camera for study by the astronauts.

Patterson, N. P.↗
NASA NTRS1977

The presence of Si I series in the ultraviolet solar spectrum - 3000 to 1200 A

Laboratory and solar data are presented which form the basis for identifying chromospheric Si I absorption lines in UV rocket spectra of the solar limb. Prints of the Si I laboratory spectrum between 1520 and 1570 A are matched with those of the chromospheric spectrum, and a striking line-to-line coincidence is observed. Individual absorption series of Si I covering the 3p(2), 3P, 1D, and 1S ground terms are tabulated in multiplet form over the wavelength range from 1517 to 3069 A. It is noted that many of the solar lines are blended with both other Si I lines and lines of other spectra.

Moore, C. E.↗
NASA NTRS1976

High-latitude observations of solar wind streams and coronal holes

Interplanetary scintillation observations of the solar wind velocity during 1973 and the first part of 1974 reveal several corotating high-speed streams. These streams, of heliographic latitudes from +40 deg to -60 deg, have been mapped back to the vicinity of the sun and have been compared with coronal holes identified in wide band XUV solar images taken during the manned portions of the Skylab mission. There is some evidence that the high-speed streams are preferentially associated with coronal holes and that they can spread out from the hole boundaries up to about 20 deg in latitude. However, this association is not one to one; streams are observed which do not map back to coronal holes, and holes are observed which do not lie at the base of streams. To the extent that a statistical interpretation is possible the association is not highly significant, but individual consideration of streams and holes suggests that the statistical result is biased somewhat against a strong correlation.

Ricket, B. J.↗
NASA NTRS1975

The intensities and profiles of XUV transition zone lines in a quiet sun region compared to a polar coronal hole

The intensities of XUV transition-zone lines from limb spectra of a quiet-sun region and a polar coronal hole are compared. The spectra were obtained with a slit spectrograph on Skylab and cover a region from -12 sec within the limb to 20 sec above it. The lines selected for comparison are formed at temperatures that range from 36,000 to 220,000 K. Lines of the higher-temperature ions, e.g. O v, are significantly less intense in the coronal hole, and lines of lower-temperature ions show little change. Profiles of selected optically thin transition-zone lines from the quiet-sun and coronal-hole spectra are also shown. The lines are broader than expected in ionization equilibrium, and bulk-motion velocities are deduced from the widths of the lines. There appears to be little, if any, statistically significant difference in the velocities obtained from the quiet-sun region and the coronal hole.

Feldman, U.↗
NASA NTRS1975

Limb-brightening curves of XUV transition zone lines in the quiet sun and in a polar coronal hole observed from Skylab

Solar limb-brightening curves are discussed for XUV spectral lines formed in the upper chromosphere and transition zone of a quiet region and a polar coronal hole. The spectra were recorded with a slit spectrograph on Skylab. The lines considered are emitted from ions formed within the temperature range from 10,000 to 220,000 K. The limb-brightening curves cover a region from -4 sec within the limb to +20 sec above it. The data from 0 sec to +20 sec are compared with predictions based on both homogeneous and inhomogeneous models of the transition zone. The limb-brightening curve of the O I line at 1355.6 A indicates that O I is formed in spicules. The limb brightening of the He II line at 1640.4 A is consistent with a temperature of formation between about 40,000 and 90,000 K for He II.

Doschek, G. A.↗
NASA NTRS1975

Ultraviolet solar identifications based on extended absorption series observed in the laboratory spectrum of Si I

The absorption spectrum of Si I in the wavelength region between 1500 and 1900 A has been photographed at high resolution. The silicon vapor was produced in a 122-cm-long King furnace at 1800 to 2300 C. Forty-two Rydberg series have been observed from the ground state terms 3p(2)3P and 1D to terms associated with the 3pns and 3pnd configurations. All of the series from these configurations with J less than 4 have been extended with the 3pnd 3D(3) levels reaching n = 56. Numerous perturbations have been observed. This laboratory work has provided the basis for extending the identification of silicon lines in the solar spectrum. Nearly all lines found in the laboratory spectrum are also found in rocket spectrograms of the solar chromosphere. More than 300 lines have been attributed to Si I. The excellent correlation between laboratory and solar Si I lines is illustrated.

Moore, C. E.↗
NASA NTRS1975

Coronal changes associated with a disappearing filament

Skylab/ATM observations of a disappearing filament near the center of the solar disk are described using XUV and H-alpha spectroheliograms, X-ray filterheliograms, and photospheric magnetograms. The temperature of the coronal plasma as the filament disappeared is estimated to have been in excess of 6 million K, and it is noted that the time history of the soft X-ray and microwave fluxes displayed the gradual-rise-and-fall (GRF) signature, suggesting that the present event may have properties that are characteristic of a wide class of long-duration X-ray and radio events. A comparison with other spatially resolved long-duration X-ray events indicates that all such long-lived bursts involve transients in the outer corona and that some two-thirds of them involve either the eruption or the major activation of a prominence. It is also found that long-lived events are characterized by the appearance of new emission loops in the lower corona during the declining phase of the X-ray emission and that these loops sometimes disappear after the X-ray events and sometimes remain indefinitely.

Sheeley, N. R., Jr.↗
NASA NTRS1975

Final S020 Skylab experiment report

After the loss of the meteroid shield required using the solar scientific airlock to erect the sun shade, methods were improvised to operate the S020 experiment on EVA's. Almost no data was obtained in the wavelength range 10 to 110 A. From 110 to 280 A the spectra were 10 to 100 time less intense than expected. A probable cause in loss of instrument sensitivity is the contamination of the filters by the spacecraft coolant. A list of observed lines in presented. Although less data was obtained than expected, several lines not previously observed were recorded; and the spectra serve to confirm many very faintly observed weak lines recorded from sounding rockets by other experiments.

Tousey, R.↗
NASA NTRS1975

The 1640.4 A H-alpha line of He II observed from Skylab

Profiles obtained from NRL Skylab solar spectra of the 1640.4 A feature identified as the H-alpha line of He II are discussed and compared with theoretical profiles derived assuming (1) collisional excitation and (2) radiative recombination as the dominant excitation mechanism. Relative intensities of this line as a function of altitude above and below the solar white-light limb are also given for a representative quiet sun region and for a polar coronal hole.

Feldman, U.↗
NASA NTRS1975

A newly observed solar feature - Macrospicules in He II 304 A

He II 304 A spectroheliograms, obtained with the NRL extreme-ultraviolet slitless spectrograph during the Skylab mission, show spikelike structures at the sun's polar limb which resemble the familiar H-alpha spicules. However, the relatively large size and long life of these He II features has led to distinguishing them by the name 'macrospicules'. The macrospicules appear as protuberances or jets, ranging from 5 to over 60 sec in length, from 5 to 30 sec in width, and from 5 to over 40 minutes in lifetime. Perhaps the most radical departure from H-alpha spicules is that macrospicules occur only within the chromospheric boundaries of coronal holes. Thus macrospicules are most easily visible over the solar poles due to the coronal holes normally present there, and much less frequently at lower latitudes during limb passage of relatively rare, low-latitude coronal holes.

Bohlin, J. D.↗