A5080546289- Solar and Space Plasma Dynamics
- Ionosphere and magnetosphere dynamics
- Astro and Planetary Science
- Stellar, planetary, and galactic studies
- Geophysics and Gravity Measurements
- Geomagnetism and Paleomagnetism Studies
- Earthquake Detection and Analysis
- Solar Radiation and Photovoltaics
- Atmospheric Ozone and Climate
- Calibration and Measurement Techniques
- Gamma-ray bursts and supernovae
- CCD and CMOS Imaging Sensors
- Planetary Science and Exploration
- Particle Accelerators and Free-Electron Lasers
- Adaptive optics and wavefront sensing
- Astrophysics and Cosmic Phenomena
- History and Developments in Astronomy
- Climate variability and models
- Scientific Research and Discoveries
- NMR spectroscopy and applications
- Advanced Optical Sensing Technologies
- Infrared Target Detection Methodologies
- Photocathodes and Microchannel Plates
- Geological and Geophysical Studies
- Complex Systems and Time Series Analysis
Lockheed Martin (United States)
1998-2018
Lockheed Martin (Australia)
2013
K Lab (United States)
2007-2012
University of Hawaii System
1992-2005
Honolulu University
1990-1991
The Interface Region Imaging Spectrograph (IRIS) small explorer spacecraft provides simultaneous spectra and images of the photosphere, chromosphere, transition region, corona with 0.33-0.4 arcsec spatial resolution, 2 s temporal resolution 1 km/s velocity over a field-of-view up to 175 x arcsec. IRIS was launched into Sun-synchronous orbit on 27 June 2013 using Pegasus-XL rocket consists 19-cm UV telescope that feeds slit-based dual-bandpass imaging spectrograph. obtains in passbands from...
We report on observations of recurrent jets by instruments onboard the Interface Region Imaging Spectrograph (IRIS), Solar Dynamics Observatory (SDO) and Hinode spacecrafts. Over a 4-hour period July 21st 2013, coronal were observed to emanate from NOAA Active 11793. FUV spectra probing plasma at transition region temperatures show evidence oppositely directed flows with components reaching Doppler velocities +/- 100 km/s. Raster maps using Si IV line all four have helical motion same sense....
We present one of the first triangulations and 3D reconstructions coronal loops, using EUVI telescopes two STEREO A B spacecraft. The triangulation loops was performed in an active region, observed with on 2007 May 9 a spacecraft separation angle αsep = 7.3°, at wavelength 171 Å. identify 30 loop structures (7 complete 23 partial segments) compute their coordinates (x,y,z) (the full are available as electronic file). quantify height range, stereoscopic measurement errors, plane inclination...
Solar spicules have eluded modelers and observers for decades. Since the discovery of more energetic type II, become a heated topic but their contribution to energy balance low solar atmosphere remains unknown. Here we give first glimpse what quiet Sun look like when observed with NASA's recently launched Interface Region Imaging Spectrograph (IRIS). Using IRIS spectra filtergrams that sample chromosphere transition region compare properties evolution as in coordinated campaign Hinode...
view Abstract Citations (92) References (24) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS H alpha Spectra of Dynamic Chromospheric Processes in Five Well-observed X-Ray Flares Canfield, Richard C. ; Penn, Matthew J. Wulser, Jean-Pierre Kiplinger, Alan L. Simultaneous H-alpha and hard X-ray (HXR) spectra were obtained for five solar flares to determine the relationship profiles nonthermal part flare represented by burst. All exhibited impulsive-phase...
The Interface Region Imaging Spectrograph (IRIS) is a NASA small explorer mission that provides high-resolution spectra and images of the Sun in 133 - 141 nm 278 283 wavelength bands. IRIS data are archived calibrated form made available to public within seven days observing. calibrations applied include dark correction, scattered light background flat fielding, geometric distortion calibration. In addition, team has absolute throughput as function been tracking changes over course mission....
Abstract We analyse one of the first coronal waves observed by STEREO/EUVI associated with a source region just behind limb, NOAA 10940. apply “wave” model proposed Attrill et al. (2007) to explain evolution bright fronts, thereby arguing that fronts and dimmings are due magnetic reconnections between expanding CME core surrounding structures. offer discussion showing this provides mechanism via which CMEs, from small can naturally become large‐scale in low corona. (© 2007 WILEY‐VCH Verlag...
The Solar Terrestrial Relations Observatory EUV telescopes have uncovered small-scale eruptive events, tentatively referred to as "mini-CMEs" because they exhibit morphologies similar large-scale coronal mass ejections (CMEs). Coronal waves and widespread diffuse dimmings followed by the expansion of are most brightly manifestations CMEs. high temporal spatial resolution data allows us detect analyze these resolve their fine structure, show that observed "mini-waves" a strong similarity...
Semiempirical atmospheric modeling attempts to match an observed spectrum by finding the temperature distribution and other physical parameters along line of sight through emitting region such that calculated agrees with one. In this paper we take a sunspot quiet Sun in EUV wavelength range 668–1475 Å from 2001 SUMER atlas Curdt et al. determine models two regions, extending photosphere overlying chromosphere into transition region. We solve coupled statistical equilibrium optically thick...
We examine the spatial relationship between solar hard X-ray sources observed with Hard X-Ray Telescope aboard Yohkoh and photospheric electric currents at Mees Solar Observatory. In 1993, Canfield et al. concluded that energetic electron precipitation tends to occur edge of sites high vertical current. They did not, however, have a direct diagnostic particle precipitation; they used Hα Stark-wing emission as proxy. this paper, we analyze images vector magnetograms six flares M/X class reach...
view Abstract Citations (38) References (19) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Electric Currents and Coronal Heating in NOAA Active Region 6952 Metcalf, T. R. ; Canfield, C. Hudson, H. S. Mickey, D. L. Wulser, J. -P. Martens, P. Tsuneta, We examine the spatial temporal relationship between coronal structures observed with soft X-ray telescope (SXT) on board Yohkoh spacecraft vertical electric current density derived from photospheric vector...
view Abstract Citations (21) References (26) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Energetics and Dynamics in a Large Solar Flare of 1989 March Wulser, Jean-Pierre ; Canfield, Richard C. Zarro, Dominic M. Maximum Mission X-ray observations National Observatory/Sacramento Peak H alpha spectra are combined large (X1.2) solar flare to test predictions chromospheric heating evaporation by nonthermal thick-target electrons. It is demonstrated that the...
Using the 2016 Mercury transit of Sun, we characterize on orbit spatial point spread functions (PSFs) for Near- (NUV) and Far- (FUV) Ultra-Violet spectrograph channels NASA's Interface Region Imaging Spectrograph (IRIS). A semi-blind Richardson-Lucy deconvolution method is used to estimate PSFs each channel. Corresponding estimates Modulation Transfer Functions (MTFs) indicate resolution 2.47 cycles/arcsec in NUV channel near 2796 Å 2.55 2814 Å. In short ( ≈1336Å ) long ≈1394Å wavelength FUV...
The Interface Region Imaging Spectrograph (IRIS) is a NASA SMall EXplorer mission scheduled for launch in January 2013. primary goal of IRIS to understand how the solar atmosphere energized. investigation combines advanced numerical modeling with high resolution UV imaging spectrograph. will obtain spectra and images space (0.4 arcsec) time (1s) focused on chromosphere transition region Sun, complex interface between photosphere corona. instrument uses Cassegrain telescope feed dual...
view Abstract Citations (12) References (25) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS A Study of Solar Flare Energy Transport Based on Coordinated H alpha and X-Ray Observations Canfield, Richard C. ; Wulser, Jean-Pierre Zarro, Dominic M. Dennis, Brian R. The temporal evolution the ratio between H-alpha to nonthermal hard X-ray emission was investigated using coordinated hard- soft-X-ray observations five solar flares (on May 7, June 23, 24, 25, 1980...
The SECCHI Extreme Ultraviolet Imager (EUVI) is a pair of EUV telescopes on the NASA STEREO mission that was successfully launched in October 2006. two telescopes, one each spacecraft observe solar corona three dimensions out to 1.7 radii, and with pixel resolution 1.59 arcsec. focus EUVI observations initiation early evolution coronal mass ejections (CMEs). This paper presents preliminary assessment on-orbit performance EUVI.
view Abstract Citations (10) References (34) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The 1991 October 24 Flare: A Challenge for Standard Models de La Beaujardiere, J. -F. ; Canfield, R. C. Hudson, H. S. Wulser, -P. Acton, L. Kosugi, T. Masuda, M9.8 solar flare of 22:30 UT presents several interesting characteristics: (1) energy release starts high in the corona; (2) primary chromospheric ribbons are initially well separated and do not move apart at an...
We give preliminary results from the first use of University Hawaii’s new Imaging Vector Magnetograph (IVM) to search for linear polarization in H‐alpha spectral line during solar flares. Such has previously been interpreted as impact 100 keV protons impacting chromosphere. The data set several advantages over previous data. First, field view is substantially larger than that used by Metcalf et al., and, second, temporal resolution (16 s) a factor two better obtained. show comparison between...