A5055861141- Solar and Space Plasma Dynamics
- Stellar, planetary, and galactic studies
- Geomagnetism and Paleomagnetism Studies
- Geophysics and Gravity Measurements
- Astro and Planetary Science
- Ionosphere and magnetosphere dynamics
- Solar Radiation and Photovoltaics
- Astronomy and Astrophysical Research
- Adaptive optics and wavefront sensing
- Atmospheric Ozone and Climate
- Computational Physics and Python Applications
- Calibration and Measurement Techniques
- History and Developments in Astronomy
- Astrophysics and Star Formation Studies
- Theology and Philosophy of Evil
- Inertial Sensor and Navigation
- Cosmology and Gravitation Theories
- Religion and Society Interactions
- Composite Structure Analysis and Optimization
- CCD and CMOS Imaging Sensors
- Gamma-ray bursts and supernovae
- Structural Load-Bearing Analysis
- Civil and Structural Engineering Research
- Planetary Science and Exploration
- Spacecraft and Cryogenic Technologies
National Solar Observatory
2008-2023
University of Arizona
1985-2023
U.S. National Science Foundation
1982-2019
Kitt Peak National Observatory
1978-2006
Association of Universities For Research In Astronomy
1982-1999
Optica
1996-1998
McMaster University
1991
United States Naval Research Laboratory
1989
Oklahoma State University
1983-1984
University of Pennsylvania
1980
Data from the Global Oscillation Network Group (GONG) project and other helioseismic experiments provide a test for models of stellar interiors thermodynamic radiative properties, on which depend, matter under extreme conditions found in sun. Current are agreement with inferences, suggests, example, that disagreement between predicted observed fluxes neutrinos sun is not caused by errors models. However, GONG data reveal subtle models, such as an excess sound speed just beneath convection...
Helioseismology requires nearly continuous observations of the oscillations solar surface for long periods time in order to obtain precise measurements sun's normal modes oscillation. The GONG project acquires velocity images from a network six identical instruments distributed around world. began full operation October 1995. It has achieved duty cycle 89 percent and reduced magnitude spectral artifacts by factor 280 power, compared with single-site observations. instrumental noise is less...
view Abstract Citations (294) References (16) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Large-scale patterns formed by solar active regions during the ascending phase of cycle 21 Gaizauskas, V. ; Harvey, K. L. J. W. Zwaan, C. Synoptic maps photospheric magnetic fields prepared at Kitt Peak National Observatory are used in investigating large-scale spatial and temporal distribution for 27 rotations between 1977 1979. The found to be distributed...
We have used Global Oscillation Network Group (GONG) magnetograms to characterize the changes in photospheric longitudinal magnetic field during 15 X-class solar flares. An abrupt, significant, and persistent change occurred at least one location within flaring active region each event. identified a total of 42 sites where such occurred. At 75% these sites, less than 10 minutes. The absolute values ranged between 30 almost 300 G, median being 90 G. Decreases measured component were twice as...
Global Oscillation Network Group data reveal that the internal structure of sun can be well represented by a calibrated standard model. However, immediately beneath convection zone and at edge energy-generating core, sound-speed variation is somewhat smoother in than it This could consequence chemical inhomogeneity too severe model, perhaps owing to inaccurate modeling gravitational settling or neglected macroscopic motion may present sun. Accurate knowledge sun's enables inferences made...
Open magnetic field lines, those which extend from the solar photosphere to interplanetary space, are traced in current-free (potential field) approximation using measured photospheric fields as a boundary condition. It is found that (1) only relatively small fraction of area connects via open lines field; (2) areas do contribute lie beneath coronal holes and within boundaries projected onto or else between loop systems an active region; (3) plane sun's equator, essentially ecliptic plane,...
Near‐ecliptic solar wind observations by Ulysses on its way to the polar regions of Sun, compared with those from IMP 8 at 1 AU, showed that high‐speed streams decay and broaden heliocentric distance Ulysses, as expected. In July 1992 while travelling south ∼13°S 5.3 encountered a recurrent stream, may also have been observed 8. The stream has total 14 times, once in each rotation through June 1993 ∼34°S. source is an equatorward extension coronal hole. From 1993, averages peak speed...
view Abstract Citations (145) References (9) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Observations of magnetic fields on two late-type dwarf stars. Robinson, R. D. ; Worden, S. P. Harvey, J. W. The detection the G8 V star Xi Boo A and K0 B 70 Oph is reported. method has been developed applied which provides estimates total field strength fraction visible stellar surface covered by fields. essence this to perform Fourier deconvolution a nonmagnetically...
Views Icon Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Twitter Facebook Reddit LinkedIn Tools Reprints and Permissions Cite Search Site Citation C. Nick Arge, Carl J. Henney, Josef Koller, Rich Compeau, Shawn Young, David MacKenzie, Alex Fay, John W. Harvey; Air Force Assimilative Photospheric Flux Transport (ADAPT) Model. AIP Conf. Proc. 25 March 2010; 1216 (1): 343–346. https://doi.org/10.1063/1.3395870 Download citation file: Ris (Zotero) Reference...
A solar magnetograph employing as detectors a pair of self-scanning 512-element integrated diode arrays is described. Coupled to 1.5-m telescope, photospheric flux small 5(10(16)) maxwells detected, corresponding in intensity DeltaI/I = 3(10(-4)) at lambda 0.8688 microm. Measured photometric properties the array are given, including MTF function wavelength, dark current temperature, completeness readout, optical and electronic fixed-pattern noise. An integrating preamplifier presented that...