Bulletin of the American Physical Society
Mid-Atlantic Section Fall Meeting 2020
Volume 65, Number 20
Friday–Sunday, December 4–6, 2020; Virtual
Session F02: Solar and X-Rays |
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Chair: Eugenio Bianchi, Pennsylvania State University |
Saturday, December 5, 2020 2:00PM - 2:36PM |
F02.00001: Solar EUV emission from the Transition Region and Corona in the context of Coronal Heating Invited Speaker: Samuel Schonfeld The solar corona is heated to MK temperatures through the conversion of magnetic to thermal energy. The precise mechanism for this energy conversion is unknown and occurs on spatial scales too small to observe with modern instrumentation. Instead, it is studied by modeling the solar atmosphere using different heating prescriptions and comparing modeled solar output with observations. We use EBTEL (Enthalpy-Based Thermal Evolution of Loops) 0D hydrodynamic simulations to investigate the EUV (extreme ultraviolet) emissions from the transition region and corona under a number of heating scenarios. We find that the transition region contributes as much or more emission as the corona, even in channels traditionally considered ``coronal'', and that the ratio caries diagnostic potential to identify heating properties. We compare these results with observed solar active regions and find broad agreement with the trends in the models. These results highlight the use of narrowband observations and the importance of properly considering the transition region in investigations of coronal heating. [Preview Abstract] |
Saturday, December 5, 2020 2:36PM - 2:48PM |
F02.00002: The possibility of rotational motion of nuclei in atoms Gh. Saleh, Reza Alizadeh Our solar system consists of the Sun as the central mass, and the planets Mercury, Venus, Earth, Mars, Jupiter, etc. All planets have rotational motion around itself and around the sun. The sun also has rotational motion. Within about every 27 days the Sun rotates once on its axis. The Sun does not rotate like the solid planets, but it rotates on its axis! This is the same as Electrons and nuclei that Electrons rotate around itself and around the nuclei. Now we have discussed about the next part, rotation of nuclei. Saleh Research Group's scientists believe that like an Electron which revolves around itself and around the nucleus, the nuclei of Atoms move at a high speed too. Nucleus movement is rotational one around itself at a fraction of the speed of light. This type of rotations causes the more stability in its structure. It is also the reason of having a rotational motion of the smallest to the largest objects such as sun, black holes and even the universe. In this article we have presented the behavior of nuclei as the most stable particle in atoms and the possibility of rotational motion of that in atoms. [Preview Abstract] |
Saturday, December 5, 2020 2:48PM - 3:24PM |
F02.00003: High-energy astrophysics enabled through high-resolution spectroscopy using nanofabricated gratings Invited Speaker: Randall McEntaffer Many future astrophysics goals require high spectral resolving power achieved at high efficiency to meet the demanding observational requirements. Questions ranging from the cycling of hot baryons within galaxies to the kinematic output of supermassive black holes to the radiation environments around exoplanet host stars can be addressed with high performance diffraction gratings. This talk will cover the development efforts on reflection grating technologies currently being performed at Penn State University. High efficiency concurrent with high resolution require new fabrication methods. Nanofabrication tools and methodologies have been employed to successfully achieve many aspects of future gratings, but more work is required. The background and status of these development efforts will be discussed. In addition, an overview of space applications currently baselining these gratings will be given. [Preview Abstract] |
Saturday, December 5, 2020 3:24PM - 3:36PM |
F02.00004: A New Extragalactic Population of Faint, Fast X-ray Transients William Brandt, Franz Bauer, Bin Luo, Jonathan Quirola-Vasquez, Yongquan Xue, Guang Yang Recently, two faint X-ray transients have been discovered in the Chandra Deep Field-South. Both lasted a few hours and are extragalactic with $z = 0.74$ (spectroscopic) and $z\approx 2.1$ (photometric), implying large total energy release. The first has been proposed to be a magnetar-powered X-ray transient resulting from a binary neutron-star merger, while the nature of the second is less clear. These findings demonstrate that a population of similar transients should exist in archival X-ray observations. We have thus recently set systematic rate constraints on such transients based on 19 Ms of Chandra surveys data. Rapid searching of incoming Chandra and XMM-Newton observations, using our methodology, should allow discovery of additional such transients for prompt follow-up. Future large-grasp X-ray missions such as Athena and Einstein Probe are needed to open the faint-fast X-ray transient discovery space fully. [Preview Abstract] |
Saturday, December 5, 2020 3:36PM - 3:48PM |
F02.00005: All Particle Cosmic Ray Spectrum from Compiled Direct Measurements of Elemental Spectra Deven Bowman, Rachel Scrandis, Eun-suk Seo The all particle spectrum of cosmic rays presents two distinct features: the `knee', in which the spectrum hardens at about $3*10^{15}$ eV, and the `ankle', at about $10^{18}$ eV, where the slope changes again. Ground based experiments have been able to collect data on both of these spectral features, but their underlying causes have yet to be determined. Space based experiments provide the ability to measure the composition of cosmic ray spectra, and cover energies ranging several magnitudes below the knee. Recent experiments such as AMS, NUCLEON, CREAM, DAMPE, and CALET have measured primary cosmic ray spectra up to $\sim10^{14}$ eV, allowing for comparison between the lower energy space based experiments and higher energy ground based experiments. This data was compiled, fit with power laws, and extended to $>10^{15}$ eV to calculate the all particle spectrum and average logarithmic atomic mass numbers. They were then compared to past ground based measurements. The extended all particle spectrum was used to calculate the expected atmospheric neutrino fluxes by utilizing the Matrix Cascade Equations toolkit. This flux was compared to IceCube data and expected atmospheric neutrino fluxes from other all particle cosmic ray spectra. [Preview Abstract] |
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