2024-03-28T23:28:35Z
https://zenodo.org/oai2d
oai:zenodo.org:1486225
2020-01-20T17:04:10Z
user-reu-pres-2018
openaire
Samra, Jenna
Marquez, Vanessa
Menzel, Marissa
2018-11-13
<p>Although mid-infrared (IR) emission lines are potentially promising for measuring coronal magnetic fields, few measurements of these lines exist. The Airborne Infrared Spectrometer (AIR-Spec) was created as a pathfinder mission that would measure emission line properties and develop technology for mid-IR coronal spectroscopy. During the 2017 eclipse over North America, AIR-Spec flew aboard the NSF/NCAR Gulfstream-V research aircraft at an altitude of 14.3 km and measured lines of Si X, S XI, Fe IX, Mg VIII, and Si IX between 1.4 and 4 microns. For the 2019 solar eclipse the AIR-Spec camera exposure time will be lengthened from 60 milliseconds to 1 second, in order to boost the signal to noise ratio. A closed loop control system will be used to reduce the image jitter below the 4.6 arcsecond Nyquist Limit for each 1 second exposure. A proof-of-concept stabilization system was implemented via a Proportional Integral Derivative (PID) controller. Image motion from the 2017 eclipse flight was recreated in the lab for testing the PID gains. The best set of PID gains resulted in a total root mean square (RMS) of 82.5% under the 4.6 arcsecond limit. The RMS for the x and y directions were 96.4% and 88.7% under the limit, respectively. A smoothing filter was applied to reduce oscillation during changes to the setpoint. Future work will include creating a 2D model, adapting the system for variable delays, and predicting delays before they exist. The upgraded closed loop stabilization system will be implemented during the 2019 solar eclipse.</p>
This work was supported by the NSF-REU Solar Physics program at SAO, grant number AGS-1560313, and NSF MRI-1531549: Development of An Airborne Infrared Spectrometer (AIR-Spec) for Coronal Emission Line Observation.
https://doi.org/10.5281/zenodo.1486225
oai:zenodo.org:1486225
Zenodo
https://zenodo.org/communities/reu-pres-2018
https://doi.org/10.5281/zenodo.1486224
info:eu-repo/semantics/openAccess
Creative Commons Attribution 4.0 International
https://creativecommons.org/licenses/by/4.0/legalcode
Solar Instruments
Solar Corona
Solar Eclipses
Instrumentation
Upgrading AIR-Spec for the 2019 Eclipse
info:eu-repo/semantics/lecture
oai:zenodo.org:1486238
2020-01-20T16:23:12Z
user-reu-pres-2018
openaire
Moore, Christopher
Suarez, Crisel
2018-11-13
<p>Solar flares are the most powerful events in the solar system. These eruptive phenomena convert magnetic energy to thermal, radiative and kinetic energy, and accelerates particles on timescales of minutes via magnetic reconnection. As a result, the local plasma can be heated to temperatures in excess of 20 MK. In addition, plasma flows from the lower chromosphere to the higher corona have been observed. Hence, elemental abundance values similar to chromospheric and photospheric values have been inferred from soft X-ray measurements. Two of the most comprehensive, independent soft X-ray studies on elemental abundance changes in solar flares disagree on the variations of certain low first ionization potential (fip) elements (Narendranath 2014, Dennis et al. 2015). The Miniature X-ray Solar Spectrometer (MinXSS) CubeSats (Moore et al. 2018) provides new spectrally resolved soft X-ray measurements at higher spectral resolution and broader spectral (0.8 – 12 keV) coverage than the measurements used in Narendranath 2014 and Dennis et al. 2015. These properties allow the MinXSS data set to unambiguously quantify solar flare variations in Fe, Ca, Si, Mg, S, Ar, and Ni abundances. Variations in elemental abundance can provide information on plasma transport and heating processes in the solar corona. I present initial results of an M5.0 flare observed by the MinXSS-1 CubeSat and how it compares to the two aforementioned studies.</p>
This work supported by the NSF-REU Solar Physics program at SAO, grant number AGS-1560313 and the NSF- Fisk- Vanderbilt Master's-to-Ph.D. Bridge Program Grant No. HRD-1547757. MinXSS-1 CubeSat mission is supported by NASA Grant NNX14AN84G.
https://doi.org/10.5281/zenodo.1486238
oai:zenodo.org:1486238
Zenodo
https://zenodo.org/communities/reu-pres-2018
https://doi.org/10.5281/zenodo.1486237
info:eu-repo/semantics/openAccess
Creative Commons Attribution 4.0 International
https://creativecommons.org/licenses/by/4.0/legalcode
Solar flares
Elemental abundance
X-ray flares
Solar Flare Plasma Transport Inferred from Elemental Abundance Changes using soft X-ray Spectra
info:eu-repo/semantics/lecture
oai:zenodo.org:1486235
2020-01-20T16:25:30Z
user-reu-pres-2018
openaire
Loftus, Kaitlyn
Saar, Steve
Merhi, Maya
2018-11-13
<p>We have created a hard x-ray solar flare catalog using short channel wavelength bands of 0.5 to 4 Å from NOAA’s Geostationary Operational Environmental Satellites (GOES) X-Ray Sensor (XRS) data for 2003 to 2018. The Where’s That Flare (WTF) catalog was developed using an automated algorithm designed to use changes in the derivative of the hard X-ray flux to identify flares. Intended to provide a complete archive of all hard X-ray solar flare events in GOES XRS data, the WTF catalog (novelly for the hard Xray) distinguishes between "simple" single peak flare events and "complex" multi-peak flare events and is sensitive to small flares near the background level. To account for the varying background level of the hard X-ray flux, the detection algorithm dynamically adapts to the local background to detect flares of all sizes and complexities. A statistical analysis of flare characteristics was performed on the WTF catalog investigating correlations between total energy, flare duration, peak flux, peak time, rise time, decay time, as well as characteristics of complex events such as number of peaks per complex event. Frequency distributions of total energy, flare duration, and number of peaks per complex event were also investigated and fit with power laws where applicable.</p>
This work is supported by NSF-REU Solar Physics program at SAO, grant
number AGS-1560313.
https://doi.org/10.5281/zenodo.1486235
oai:zenodo.org:1486235
Zenodo
https://zenodo.org/communities/reu-pres-2018
https://doi.org/10.5281/zenodo.1486234
info:eu-repo/semantics/openAccess
Creative Commons Attribution 4.0 International
https://creativecommons.org/licenses/by/4.0/legalcode
Catalogs
Solar flares
X-ray flares
Where's That Flare: A Comprehensive Hard X-Ray Solar Flare Catalog
info:eu-repo/semantics/lecture
oai:zenodo.org:1486242
2020-01-20T15:15:49Z
user-reu-pres-2018
openaire
Allen, Branden
Hong, Jae Sub
Nieves, Christian
2018-11-13
<p>The OSIRIS-REx spacecraft, launched on September 2016, is a NASA asteroid sample return mission to classify the near-Earth asteroid 101955 Bennu among the different meteorite groups. As part of the Regolith X-ray Imaging Spectrometer (REXIS), built by students in MIT and Harvard, the Solar X-ray Monitor (SXM), mounted on the Sun-facing side of the spacecraft, will measure the Solar X-rays incident to both Bennu and the OSIRIS-REx spacecraft. In conjunction with the data collected by REXIS’s primary spectrometer, the information provided by the SXM measurements will help reconstruct the elemental abundance of the asteroid.<br>
The work presented here is the analysis and characterization of data taken from angular response measurements made with the SXM flight spare model, utilizing a <sup>55</sup>Fe radiation source. From the data, plots of the count rate variability and off-axis response along the SXM FoV were made. In addition, individual measurements of the angular response tests were grouped according to their integration time and examined for variations in energy resolution and signal-to-noise ratio for the 5.9 keV and 6.5 keV iron emission lines. The goal of this project is to provide useful information that will help the calibration of the SXM on the OSIRIS-REx spacecraft for the fitting of the Solar spectra.</p>
This work supported by the NSF-REU Solar Physics program at SAO, grant number AGS-1560313
https://doi.org/10.5281/zenodo.1486242
oai:zenodo.org:1486242
Zenodo
https://zenodo.org/communities/reu-pres-2018
https://doi.org/10.5281/zenodo.1486241
info:eu-repo/semantics/openAccess
Creative Commons Attribution 4.0 International
https://creativecommons.org/licenses/by/4.0/legalcode
X-ray detectors
Solar X-ray emission
Meteorite composition
Angular Response Characterization of the REXIS Solar X-ray Monitor (SXM)
info:eu-repo/semantics/lecture
oai:zenodo.org:1486257
2020-01-20T15:23:31Z
user-reu-pres-2018
openaire
Raymond, John
Shen, Chengcai
Prchlik, Jakub
Waczak, John
2018-11-13
<p>In this study we present a nonequilibrium ionization analysis of a coronal shock driven by a coronal mass ejection (CME) observed on June 13, 2010. Using the Solar Dynamics Observatory’s Atmospheric Imaging Assembly (AIA), observations of the CME were made in the 171, 193, 211, and 335 Å channels with a corresponding spherical shock present in the 193 and 211Å channels. We constrain previously reported pre and post shock electron temperatures of 1.8 and 2.8 MK at various positions along the shock using a fast FORTRAN program to solve the time-dependent ionization equations for abundant elements in the coronal plasma. Future work will use these temperatures and densities with the magnetohydrodynamic jump conditions to derive further information about the shock.</p>
This work is supported by the NSF-REU solar physics program at SAO, grant number AGS-
1560313
https://doi.org/10.5281/zenodo.1486257
oai:zenodo.org:1486257
Zenodo
https://zenodo.org/communities/reu-pres-2018
https://doi.org/10.5281/zenodo.1486256
info:eu-repo/semantics/openAccess
Creative Commons Attribution 4.0 International
https://creativecommons.org/licenses/by/4.0/legalcode
time-dependent ionization
shock waves
coronal mass ejections
Nonequilibrium Ionization Analysis of a Coronal Shock Driven by a CME
info:eu-repo/semantics/lecture
oai:zenodo.org:1486249
2020-01-20T15:59:25Z
user-reu-pres-2018
openaire
Foster, Adam
Vázquez Pérez, Germán
2018-11-13
<p>The origin of the diffuse soft X-ray background has always been ground for many questions and debates. Previous investigations have concluded that this background radiation could be mostly due to charge exchange (CX), caused by the interaction between highly energized ions from the solar winds and neutral hydrogen and helium atoms. In 2014, simplified CX models were constructed, which successfully fit the high-resolution spectral data from the Diffuse X-ray Spectrometer mission (DXS), flown in 1993 (Smith, 2014). This model has since been deployed to analyze potential CX in a range of other plasmas (Zhang et al., 2017). In 2017, updated CX cross section data was released by the Kronos project, including velocity dependent cross sections for all ions. In this project, we incorporate this data into the CX models, then compare the two versions of the AtomDB Charge Exchange Model (ACX) by re-analyzing the DXS data for the solar winds. Our results show significant changes in the spectrum for some ions, but an overall improvement in the model fit.</p>
This project is supported by the Smithsonian's Minority Awards Internship program
https://doi.org/10.5281/zenodo.1486249
oai:zenodo.org:1486249
Zenodo
https://zenodo.org/communities/reu-pres-2018
https://doi.org/10.5281/zenodo.1486248
info:eu-repo/semantics/openAccess
Creative Commons Attribution 4.0 International
https://creativecommons.org/licenses/by/4.0/legalcode
X-ray sources: diffuse background
Solar astronomy: solar wind
Improving the Spectral Fit for the Diffuse Soft X-ray Background using ATOMDB Charge Exchange Models
info:eu-repo/semantics/lecture
oai:zenodo.org:1486247
2020-01-20T15:41:21Z
user-reu-pres-2018
openaire
Shen, Chengcai
Murphy, Nick
Dupont, Marcus
2018-11-13
<p>Non-equilibrium ionization (NEI) is a key process often times ignored when modeling astrophysical plasmas whose thermodynamical timescales are much shorter than the timescales for ionization and recombination. In this paper, we use magnetohydrodynamics (MHD) models alongside numerical NEI simulations to calculate synthetic charge state distributions during the Whole Sun Month interval (CR)-1913 (1996, 22 August to 1996, 18 September), and compare them with in-situ measurements made with the Ulysses Solar Wind Ion Spectrometer Composition (SWICS) instrument. The key ndings of our analysis have: (1) shown that the solar wind speeds at 20 R<sub>s</sub> calculated by the <em>Magnetohydrodynamics Around a Sphere</em> (MAS) model were not in agreement with the Ulysses observations; (2) measured the "freeze-in" distance for each ion observed by the SWICS instrument to determine a possible correlation between when the ionization states become fixed and their expansion into the solar wind; (3) shown how di erent charge state densities and abundance ratios compared with observation.</p>
This work supported by NSF SHINE Grant AGS-1723313.
https://doi.org/10.5281/zenodo.1486247
oai:zenodo.org:1486247
Zenodo
https://zenodo.org/communities/reu-pres-2018
https://doi.org/10.5281/zenodo.1486246
info:eu-repo/semantics/openAccess
Creative Commons Attribution 4.0 International
https://creativecommons.org/licenses/by/4.0/legalcode
Solar Wind
Comparative Study of the Solar Wind: Modeling Charge State Distributions in the Heliosphere
info:eu-repo/semantics/lecture
oai:zenodo.org:1486253
2020-01-20T15:30:29Z
user-reu-pres-2018
openaire
Madsen, Chad
DeLuca, Ed
Bacon, Amanda
2018-11-13
<p>We present a study of O IV density diagnostics in the far ultraviolet (FUV) spectra of UV bursts. UV bursts appear as compact, short-lived brightenings observed in active regions. The FUV spectra of UV bursts exhibit peculiar properties that suggest they are signatures of magnetic reconnection deeply embedded in the cool solar chromosphere; these include intensification and broadening/splitting of emission lines, the presence of optically thin Si IV 1393.8/1402.8 Å emission lines that form at transition region temperatures (<span class="math-tex">\(\ge\)</span> 80,000 K), and the presence of absorption features from cool metallic ions (Ni II 1393.3 Å and Fe II 1392.8 Å). Improving our understanding of these bursts will give us insight into how they contribute to the heating of the lower solar atmosphere. In particular, it is important to constrain the formation altitudes of these events, which can be estimated via lower-bound measurements of electron densities using O IV and Si IV emission lines. However, it is unclear how often the forbidden O IV 1401.2 Å line appears in UV burst spectra due to its potential to extinguish at high electron densities as a result of collisional de-excitation. This work will determine how often this critically important spectral feature arises in UV burst events. We locate UV bursts in AR11850 over nine observations from 24-27 September 2013 using data from the Interface Region Imaging Spectrograph (IRIS), which provides simultaneous imaging and spectroscopic data of the upper chromosphere and transition region in the far and near ultraviolet (NUV). We detect UV bursts by applying a four-parameter single-Gaussian fit to the Si IV 1393.8 Å emission line. We perform cuts in the 4-D parameter space to isolate the UV burst population, then we manually inspect the remaining spectra for signs of Ni II 1393.3 Å absorption. We use the resulting sample to look for instances of the O IV 1401.2 Å emission line. With the intent of obtaining a distribution of its statistical signi cance, we measure the total integrated intensities and their uncertainties for each O IV line associated with a UV burst. We find that 33.62% of the sampled O IV lines have signal-to-noise ratios above 3.0, which demonstrates that electron density and altitude estimates are possible for a sizable fraction of UV bursts.</p>
This work is supported by the NSF-REU Solar Physics program at SAO, grant number AGS-1560313.
https://doi.org/10.5281/zenodo.1486253
oai:zenodo.org:1486253
Zenodo
https://zenodo.org/communities/reu-pres-2018
https://doi.org/10.5281/zenodo.1486252
info:eu-repo/semantics/openAccess
Creative Commons Attribution 4.0 International
https://creativecommons.org/licenses/by/4.0/legalcode
Solar activity
Solar chromosphere
The Prevalence of O IV Density Diagnostics in UV Burst Spectra
info:eu-repo/semantics/lecture
oai:zenodo.org:1486244
2020-01-20T15:02:34Z
user-reu-pres-2018
openaire
Karna, Nishu
Savcheva, Antonia
Czyzewski, Austin
2018-11-13
<p>In this study, the magnetic configuration of a coronal sigmoid is presented. The sigmoid was observed by Hinode/XRT and SDO/AIA in the NOAA active region 12665 between July 6th-18th, 2017. We construct a Non-Linear Force-Free Field (NLFFF) model of a sigmoid observed on July 13th 2017 at 18:22 UTC using the flux-rope insertion (FR) method and relaxed the magnetic field toward a force-free state using magnetofrictional relaxation (MF). The NLFFF model produces the 3D coronal magnetic field constrained by observed coronal structures and photospheric magnetograms. SDO/HMI magnetograms were used as input of the models. The resulting magnetic field configurations were compared with Hinode/XRT and SDO/AIA images of the same region to determine the best-fit model. The sigmoid is modeled in both stable and unstable states to represent various stages of evolution in the sigmoid; the best-fit stable model has a poloidal flux of -3E10 Mx and axial flux of 2E21 Mx, whereas the best-fit unstable model has a poloidal flux of -1E10 and an axial flux of 5e21. Additionally, similar models were produced for a time earlier in the development of the active region on July 12th, 2017 at 03:17 UTC where a small jet is observed in the elbow of the sigmoid. The goal of our study is to reproduce the pre-flare configuration so that we can understand the eruption and have a NLFFF model for the magnetic environment in which the jet is erupting.</p>
This work was supported by NSF-REU Solar Physics program at SAO, grant number AGS-1560313
https://doi.org/10.5281/zenodo.1486244
oai:zenodo.org:1486244
Zenodo
https://zenodo.org/communities/reu-pres-2018
https://doi.org/10.5281/zenodo.1486243
info:eu-repo/semantics/openAccess
Creative Commons Attribution 4.0 International
https://creativecommons.org/licenses/by/4.0/legalcode
Reconstructing NOAA 12665 Sigmoidal Active Region
info:eu-repo/semantics/lecture
oai:zenodo.org:1486233
2020-01-20T17:03:21Z
user-reu-pres-2018
openaire
Hertz, Ed
Cheimets, Peter
Moraga, Paula
2018-11-13
<p>The objective of this project is to integrate existing software programs into a single software interface that will allow a user to align Arcus critical angle transmission (CAT) gratings before they are bonded to their frames, making grating facets. CAT gratings allow x-ray photons to pass through at an angle that matches the grazing incidence angle, hence the name critical angle transmission gratings. Arcus, an x-ray spectrometer, will require 704 aligned grating facets. Because these gratings are produced with a small amount of error, they must be aligned in 6 axes (translation and rotation) before they are bonded to a facet frame. This is done so that any two of the resulting grating facets can be interchangeable with each other. The current process used to align these gratings requires two people to exchange measurements and to manually input corrections to alignment: one to control the movement of the Hexapod, a six-legged stage on which the grating will be placed, and the other to perform the data analysis used to calculate the required adjustments. This is impractical for the large scale operation that will be required for the flight-build, causing a need for a simplified alignment process that is completely and comprehensively planned out and that eliminates the possibility of operator error. This project specifically focuses on rewriting the existing C# and Matlab programs used to record alignment data and demonstrate when alignment has been achieved. The code written in Python will take data, indicate which Hexapod axes to move to achieve alignment and determine that the misalignment has been completely removed. There are future plans to finish building the GUI by including code that will aid in the movement of the Hexapod, and building the user interface around it.</p>
This work was supported through the NSF-REU Solar Physics program at SAO, grant number AGS-1560313
https://doi.org/10.5281/zenodo.1486233
oai:zenodo.org:1486233
Zenodo
https://zenodo.org/communities/reu-pres-2018
https://doi.org/10.5281/zenodo.1486232
info:eu-repo/semantics/openAccess
Creative Commons Attribution 4.0 International
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Astronomical optics
Interdisciplinary astronomy
Spectrometers
Constructing a User Interface for the Alignment of CAT Gratings
info:eu-repo/semantics/lecture
oai:zenodo.org:1486240
2020-01-20T15:31:46Z
user-reu-pres-2018
openaire
Moore, Christopher
Reeves, Kathy
Garza, Sierra
2018-11-13
<p>We investigated the relationship between the photospheric magnetic and coronal soft X-ray flux. The soft X-ray data is from Hinode/XRT (Al-Mesh, Al-Poly, Be-Thin) and MinXSS/X123 cubesat, extreme ultraviolet data is from SDO/AIA (94 angstrom and FeXVIII), and magnetic field data is from SDO/HMI (total B, positive, negative, and unsigned line-of-sight) during June 2016 to April 2017. SDO/HMI line-of-sight (los) data, at threshold values of 316 and 1000 gauss, and data number per second from each of the Hinode/XRT data filters portray a positive correlation between all data sets shown in time series plots. This indicates that the change in radiation energy is proportional to the change in magnetic flux over time. Currently, Hinode/XRT data displays a stronger correlation to the SDO/HMI los above a 316 gauss threshold than SDO/AIA data from scatter plots. In future work, we will compare these results with MinXSS/X123 data in order to understand the spectral components, temperature structure, and elemental abundance variation with the photospheric magnetic field.</p>
This work is supported by the NSF-REU Solar Physics program at SAO, grant number AGS-1560313. The MinXSS-1 CubeSat mission is supported by NASA Grant NNX14AN84G.
https://doi.org/10.5281/zenodo.1486240
oai:zenodo.org:1486240
Zenodo
https://zenodo.org/communities/reu-pres-2018
https://doi.org/10.5281/zenodo.1486239
info:eu-repo/semantics/openAccess
Creative Commons Attribution 4.0 International
https://creativecommons.org/licenses/by/4.0/legalcode
Ephemeral Active Region
Solar magnetic fields
Solar X-ray emission
The Relationship Between Solar Surface Magnetic Field and Coronal Soft X-Ray Filter Images
info:eu-repo/semantics/lecture