A5064419983- Solar and Space Plasma Dynamics
- Geomagnetism and Paleomagnetism Studies
- Astro and Planetary Science
- Stellar, planetary, and galactic studies
- Ionosphere and magnetosphere dynamics
- Inertial Sensor and Navigation
- Solar Radiation and Photovoltaics
- Geological and Geophysical Studies
- Geophysics and Gravity Measurements
- Superconducting Materials and Applications
- Nuclear Physics and Applications
- SAS software applications and methods
- Earthquake Detection and Analysis
- Astronomical Observations and Instrumentation
- Particle accelerators and beam dynamics
- Atomic and Subatomic Physics Research
- Geophysical and Geoelectrical Methods
- Laser-induced spectroscopy and plasma
- Image Processing and 3D Reconstruction
- Gamma-ray bursts and supernovae
- Global Energy and Sustainability Research
- Photovoltaic System Optimization Techniques
- Climate Change Policy and Economics
- Crime Patterns and Interventions
- Magnetic confinement fusion research
Southwest Research Institute
2012-2022
Goddard Space Flight Center
2009-2010
Catholic University of America
2010
University of Colorado Boulder
2007-2009
Solar flares, coronal mass ejections, and indeed phenomena on all scales observed the Sun, are inextricably linked with Sun's magnetic field. The solar surface is covered features many spatial scales, which evolve differing timescales: largest features, sunspots, follow an 11-year cycle; smallest seem to no cycle. Here, we analyze magnetograms from Heliospheric Observatory (SOHO)/Michelson Doppler Imager (full disk high resolution) Hinode/Solar Optical Telescope determine fluxes of currently...
Feature tracking and recognition are increasingly common tools for data analysis, but typically implemented on an ad-hoc basis by individual research groups, limiting the usefulness of derived results when selection effects algorithmic differences not controlled. Specific that affected include solar magnetic turnover time, distributions sizes, strengths, lifetimes features, physics both small scale flux emergence small-scale dynamo. In this paper, we present a detailed comparison between...
We study the magnetic properties of small-scale transients in coronal hole. found all brightening events are associated with bipolar regions and caused by flux emergence followed cancellation pre-existing newly emerging flux. In hole, 19 22 have a single stable polarity which does not change its position time. eleven cases this is dominant polarity. The hole form largest concentration terms size while opposite distributed small concentrations. number elements four times higher than...
We investigate the origin of small-scale flux concentrations in quiet Sun. In apparent violation physical requirement for balance, 94% features containing newly detected are unipolar at a resolution 1.2''. analyze 2619 these emergences an image sequence from SOHO MDI magnetograph and compare ensemble average to model asymmetric bipolar emergence that could principle hide opposing under noise floor MDI. examine statistical consequences this mechanism find it cannot be responsible more than...
Understanding the behavior of weak magnetic fields near detection limit current instrumentation is important for determining flux budget solar photosphere at small spatial scales. Using 03-resolution magnetograms from Solar Optical Telescope's Narrowband Filter Imager (NFI) on Hinode spacecraft, we confirm that previously reported apparent unipolar emergence seen in intermediate-resolution indeed coalescence existing flux. We demonstrate similar but smaller events NFI are also likely to...
The removal of magnetic flux from the quiet-Sun photosphere is important for maintaining statistical steady state field there, determining budget Sun, and estimating rate energy injected into upper solar atmosphere. Magnetic feature death a measurable proxy detectable flux, either by cancellation (submerging or rising loops, reconnection in photosphere) dispersal flux. We used SWAMIS tracking code to understand how nearly 2 × 104 features die an hour-long sequence Hinode/SOT/NFI magnetograms...
Long-lived rotational and meridional flows are important ingredients of the solar cycle. Magnetic field images have typically been used to measure these on surface by cross-correlating thin longitudinal strips or square patches across sufficiently long time gaps. Here, I use one month SDO/HMI line-of-sight magnetic observations, combined with SWAMIS feature tracking algorithm motion individual features in magnetograms. By controlling for perturbations due short-lived false motions from...
We explore the nature of small-scale solar dynamo by tracking magnetic features. investigate two previously-explored categories dynamo: shallow and deep. Recent modeling work on has produced a number scenarios for how strong network concentration can influence formation polarity nearby These have measurable signatures, which we test here using magnetograms from Narrowband Filter Imager (NFI) Hinode. find no statistical tendency newly-formed features to cluster around or away concentrations,...
Chromospheric rapid blueshifted excursions (RBEs) are suggested to be the disk counterparts of type II spicules at limb and believed contribute coronal heating process. Previous identification RBEs was mainly based on feature detection using Dopplergrams. In this paper, we study 2011 October 21 in a very quiet region center, which were observed with high-cadence imaging spectroscopy Ca 8542 A line from Interferometric Bidimensional Spectrometer (IBIS). By an automatic spectral analysis...
Bipolar magnetic regions (BMRs) are the cornerstone of solar variability. They tracers large-scale processes that give rise to cycle, shapers corona, building blocks field, and significant contributors free-energetic budget gives flares coronal mass ejections. Surprisingly, no homogeneous catalog BMRs exists today, in spite existence systematic measurements field since early 1970's. The purpose this work is address deficiency by creating a homogenous from 1970's until present. For purpose,...
Abstract We study the magnetic field structure and evolution for 26 X-ray brightening events in coronal holes quiet Sun regions, including bright points jets. found that all are associated with bipolar regions caused by flux emergence followed cancellation. The emission fluctuations seen reoccurring cancellation footpoints. An jet presents similar behaviour footpoints but its rate is much higher than point. Comparing Sun, we do not find differences their corresponding behavior.
This article describes the development of a videotape targeted at persons under supervision criminal justice system. The seeks to encourage those who use illicit drugs enter drug treatment and motivate risk for exposure human immunodeficiency virus (HIV) alter behaviors that may transmit infection. system presents an important opportunity deliver such messages, particularly large population briefly detained in jail or lockup released without subsequent incarceration. Evidence suggests that,...
We present a set of tools for detecting small-scale solar magnetic cancellations and the disk counterpart type II spicules (the so-called Rapid Blueshifted Excursions (RBEs)), using line-of-sight photospheric magnetograms chromospheric spectroscopic observations, respectively. For tracking cancellation, we improve Southwest Automatic Magnetic Identification Suite (SWAMIS) so that it is able to detect certain obscure can be easily missed. RBEs, use normalized reference profile reduce...
We present a set of tools for detecting small-scale solar magnetic cancellations and the disk counterpart type II spicules (the so-called Rapid Blueshifted Excursions (RBEs)), using line-of-sight photospheric magnetograms chromospheric spectroscopic observations, respectively. For tracking cancellation, we improve Southwest Automatic Magnetic Identification Suite (SWAMIS) so that it is able to detect certain obscure can be easily missed. RBEs, use normalized reference profile reduce...