Bulletin of the American Physical Society
APS April Meeting 2017
Volume 62, Number 1
Saturday–Tuesday, January 28–31, 2017; Washington, DC
Session Y3: Solar Physics |
Hide Abstracts |
Sponsoring Units: DAP Chair: Eric Cramer, University of Alabama, Huntsville Room: Maryland C |
Tuesday, January 31, 2017 1:30PM - 1:42PM |
Y3.00001: On a few global properties of (a MHD) interstellar medium and its impact on the solar wind Daniel Berdichevsky We present quantitative results on the possibility that the Solar Wind and the local molecular nebula (LMN) achieve dynamic equilibrium. We require equilibrium between the pressure exerted by the Solar Wind and the reaction to it of the LMN, assumed to have a magneto-matter nature. We assume the MLN having: (i) a simple homogeneous distribution of matter coalescent to a magnetic field in a cylindrical geometry (Berdichevsky, 2016), (ii) the in-situ by Voyager observed properties (a fraction of 9/10 neutrals and 1/10 ionized matter, with a number N$_{\mathrm{e\thinspace }}$\textasciitilde 0.1 of free electrons, and a \textless \textbf{B}\textgreater \textasciitilde 0.5 nT). Additional consideration is given to the needed permeability of the medium to make it capable of supporting stresses related to its state. The assumed state of self organization of matter and magnetic field (magneto-matter state) has proven useful interpretation of anomalous thermodynamic of the gas of electrons contained in flux-tubes with a twist, low-beta, often observed at 1 AU in the interplanetary medium, Berdichevsky and Shefers, 2015. Berdichevsky, D.B., APS Spring Meeting, 2016; Berdichevsky, D.B., and K., Schefers, ApJ, 803, 70, 2015, doi: 10.1088/0004-637X/805/1/70 [Preview Abstract] |
Tuesday, January 31, 2017 1:42PM - 1:54PM |
Y3.00002: Observation of Reconstructable Radio Waveforms from Solar Flares with the Askaryan Radio Array (ARA) Brian Clark The Askaryan Radio Array (ARA) is an ultra-high energy ($>10^{17}$ eV) neutrino detector in phased construction at the South Pole. The full detector will consist of $\sim$37 autonomous stations of antennas which search for the radio pulses produced by neutrino interactions in the Antarctic ice. Three of the proposed detectors have been installed at up to 200m depth, with an additional two slated for deployment in Austral summer 2017. A prototype of the detector was deployed in January 2011, in time to serendipitously observe the relatively active solar month of February. In this talk, we will present preliminary results from an analysis of radio waveforms associated with an X-class solar flare observed in this prototype station. These are the first reconstructable events of natural origin seen by ARA, and could potentially be a powerful calibration source for the array. [Preview Abstract] |
Tuesday, January 31, 2017 1:54PM - 2:06PM |
Y3.00003: Very-High-Energy Solar Gamma Rays From Cosmic-Ray Interactions Bei Zhou, Kenny Ng, John Beacom, Annika Peter, Cartsen Rott Cosmic-ray induced gamma rays from the Sun has been observed up to ~100 GeV. However, there are no theoretical predictions beyond 10 GeV. We provide the first calculation of the hadronic disk component in TeV-PeV, where solar magnetic fields can be ignored. We also consider the leptonic gamma-ray halo, taking into account electrons from local pulsars. With Fermi and soon HAWC & LHAASO observations, our results provide new insights on local cosmic rays, solar magnetic fields, and solar dark matter studies. [Preview Abstract] |
Tuesday, January 31, 2017 2:06PM - 2:18PM |
Y3.00004: Fermi Large Area Telescope observations of high-energy gamma-ray emission from Solar flares Melissa Pesce Rollins The Fermi Large Area Telescope (LAT) observations of the active Sun provide the largest sample of detected solar flares with emission greater than 30 MeV to date. These include detections of impulsive and sustained emission, extending up to ~20 hours in the case of the 2012 March 7 X-class flares. These high-energy flares are coincident with GOES X-ray flares of X, M and C classes as well as very fast Coronal Mass Ejections (CME). We will present results from the First Fermi-LAT solar flare catalog covering the majority of Solar Cycle 24 including correlation studies with the associated Solar Energetic Particles (SEP) and CMEs. [Preview Abstract] |
Tuesday, January 31, 2017 2:18PM - 2:30PM |
Y3.00005: Fermi Large Area Telescope Observations of High-Energy Gamma-ray Emission From Behind-the-limb Solar Flares Nicola Omodei, Melissa Pesce-Rollins, Vahe Petrosian, Wei Liu, Fatima Rubio da Costa, Sergei Golenetskii, Larisa Kashapova, Sam Krucker, Valentin Palshin Fermi LAT $>$30 MeV observations of the active Sun have increased the number of detected solar flares by almost a factor of 10 with respect to previous space observations. Of particular interest are the recent detections of three solar flares whose position behind the limb was confirmed by the STEREO-B spacecraft. These observations sample flares from active regions originating from behind both the eastern and western limbs and include an event associated with the second ground level enhancement event (GLE) of the 24th Solar Cycle. While gamma-ray emission up to tens of MeV resulting from proton interactions has been detected before from occulted solar flares, the significance of these particular events lies in the fact that these are the first detections of $>$100 MeV gamma-ray emission from footpoint-occulted flares. These detections present an unique opportunity to diagnose the mechanisms of high-energy emission and particle acceleration and transport in solar flares. We will present the Fermi-LAT, RHESSI and STEREO observations of these flares and discuss the various emission scenarios for these sources. [Preview Abstract] |
Tuesday, January 31, 2017 2:30PM - 2:42PM |
Y3.00006: Observations of the Moon and the Sun using TeV Gamma Rays and Cosmic Rays Mehr Un Nisa, Zig Hampel The Sun and Moon provide unique targets for studies of cosmic rays and gamma rays above 1 TeV. By observing the deficits (or "shadows") in the flux of Galactic cosmic rays created by the Moon and the Sun, we can measure particle deflection in the geomagnetic field, estimate the fraction of hadronic and leptonic antiparticles in the cosmic-ray flux, and probe hard-to-observe properties of the solar magnetic field. In addition, TeV gamma rays from the solar disk can be used to study cosmic-ray interactions in the solar photosphere and place limits on the annihilation of dark matter captured by the Sun's gravity. The High Altitude Water Cherenkov (HAWC) Observatory, operating in central Mexico since the end of 2014, is the only facility currently capable of observing TeV cosmic rays and gamma rays from the Moon and the Sun. We describe the first year of observations of the lunar and solar disks with HAWC, and discuss prospects for conducting solar and Galactic astrophysics with these data. [Preview Abstract] |
Tuesday, January 31, 2017 2:42PM - 2:54PM |
Y3.00007: Solar Energetic Particle Spectra Measured with PAMELA James Ryan, Alessandro Bruno, Mirko Boezio, Ulisse Bravar, Eric Christian, de Nolfo Georgia, Matteo Martucci, Matteo Merge, Riccardo Munini, Roberta Sparvoli, Steven Stochaj We have measured the event integrated spectra from several SEP events from 2006 to 2014 in the energy range starting at 80 MeV and extending well above the neutron monitor threshold. The PAMELA instrument is in a high inclination, low Earth orbit and has access to SEPs when at high geographic latitudes. This means that the spectra have been assembled from regularly spaced measurements with gaps during the course of the event. Furthermore, the field of view of PAMELA is small and during the high latitude passes it scans a wide range of asymptotic directions as the spacecraft moves. Correcting for data gaps and solid angle effects, we have compiled event-integrated intensity spectra that typically exhibit power law shapes in energy with an exponential roll over. The events analyzed include two, maybe three, GLEs. In those cases the roll over energy lies above the neutron monitor threshold (1 GV) while the others are lower. We see no qualitative difference between the spectra of GLE vs. non-GLE events. [Preview Abstract] |
Tuesday, January 31, 2017 2:54PM - 3:06PM |
Y3.00008: The Astrophysics of the Solar Corona at the August 21, 2017, American Total Solar Eclipse Jay Pasachoff The first total solar eclipse to cross the United States from coast to coast in 99 years will occur on August 21, 2017, with a 70-mile-wide path of totality from Oregon to South Carolina, with cloudiness statistics more favorable in the northwest than in the southeast. I will discuss a series of observations of the solar corona made during recent solar eclipses and related spacecraft observations. I will further discuss plans for using the 2017 eclipse for furthering our studies of the heating of the solar corona to millions of kelvins, of the dynamics of coronal mass ejections and polar plumes, and of the response of the corona to the solar magnetic field. I will conclude by discussing public-education plans for the eclipse, during which the whole U.S., Mexico, Central America, and Canada will enjoy a partial eclipse. My work at solar eclipses has recently been supported by the NSF and the Committee for Research and Exploration of the National Geographic Society, and I thank them both for research grants for our scientific studies of the 2017 total eclipse, including AGS-1602461 from the NSF and 987816 from National Geographic. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700