Bulletin of the American Physical Society
2018 Annual Meeting of the APS Mid-Atlantic Section
Volume 63, Number 20
Friday–Sunday, November 9–11, 2018; College Park, Maryland
Session G02: Space Physics |
Hide Abstracts |
Chair: Miguel A. Mostafa, Pennsylvania State University Room: Edward St. John 2212 |
Saturday, November 10, 2018 4:00PM - 4:36PM |
G02.00001: Investigating Mysteries of Cosmic Rays with Space-based Experiments Invited Speaker: Eun-Suk Seo One of the most exciting possibilities in cosmic ray research is the potential to discover new phenomena. Elementary particles were discovered in cosmic rays before modern-day accelerators became available to study their detailed properties. Since the discovery of cosmic ray antiprotons in 1979 using a balloon-borne magnet spectrometer, a series of magnet spectrometers have been flown to search for the signature of dark matter annihilation/decay in antiprotons and positrons. AMS-02 on the International Space Station (ISS) is currently providing measurements of various particles and anti-particles, including positrons and antiprotons, with unprecedented precision. In particular, excess positrons generated a lot of excitement due to their possible explanation of dark matter. In addition, the JAXA-led CALET ISS mission and the DAMPE Chinese Satellite have been in operation since 2015. Most recently, NASA’s ISS-CREAM was launched on SpaceX-12 and successfully installed on the ISS in 2017. These missions provide complementary measurements exploring energies higher than previously possible to constrain cosmic ray propagation models in search of dark matter and the origin of cosmic rays. Recent results, their implications, and the outlook for the field will be presented.
|
Saturday, November 10, 2018 4:36PM - 4:48PM |
G02.00002: Improving Particle Identification with Resistant Track Finding for the ISS-CREAM Calorimeter Jon Paul Lundquist Moving from Antarctic balloons to the International Space Station the Cosmic Ray Energetics And Mass detector (ISS-CREAM) has begun taking the highest energy direct measurements of cosmic ray (CR) particles ever attempted. ISS-CREAM will investigate how the energy distributions evolve, for protons all the way to iron nuclei, and will provide important information for models of galactic sources and CR propagation. The CR particle identification can be significantly improved by tracking particle-detector interactions from the calorimeter (for energy measurement) back to the Silicon Charge Detector for atomic number determination. A track finding algorithm resistant to such issues as particle multiplicity, backscatter, and noise is outlined. |
Saturday, November 10, 2018 4:48PM - 5:00PM |
G02.00003: Systematic Effects in the Measurement of Large Scale Anisotropies Miguel A Mostafa, Lindsey Diehl The High Altitude Water Cherenkov (HAWC) Observatory detects cosmic rays and gamma rays in the multi-TeV energy range. An unexpected, and still unexplained, large scale anisotropy is observed in the spatial distribution of the arrival directions of the air showers (initiated by both cosmic rays and gamma rays). I studied the arrival directions of both cosmic rays and gamma rays detected with the HAWC Observatory as a function of energy. I also compared my observations with simulated air showers. I will present the observed oscillations in local azimuth and a comparison with the expectations. |
Saturday, November 10, 2018 5:00PM - 5:12PM |
G02.00004: Energy limits for acceleration of cosmic rays in supernova remnants Vladimir Ptuskin, Eun-Suk Seo, Vladimir Zirakashvili Cosmic ray acceleration by astrophysical shocks in supernova remnants of different types is briefly reviewed. Results of numerical modeling for young and middle-age supernova remnants and acceleration in interstellar bubbles created by powerful stellar winds of supernova progenitors are presented. Non-thermal electromagnetic and neutrino emission produced by accelerated particles in supernova remnants is compared with the available data of radio, X-ray, gamma-ray and neutrino astronomy. |
Saturday, November 10, 2018 5:12PM - 5:24PM |
G02.00005: Assessing SOLIS 854.2 A Diagnostics of the Chromospheric Magnetic Field Gaya Ganesan, Sasha Khidekel, Gregory Fleishman, Gelu Nita Here we report the result of a study in which we attempted to quantify the heights at which chromospheric magnetic field measurement constraints may be applied to the nonlinear force free field (NLFFF) extrapolations. To make this assessment, we produced NLFFF magnetic data cubes from vector magnetic field maps obtained by the HMI instrument onboard the Solar Dynamics Observatory (SDO), which we compared with ready-to-use line of sight (LOS) chromospheric magnetic field maps from the National Solar Observatory’s SOLIS instrument, produced by the weak-field approximation method from Ca 8542 spectral line measurements. We modeled five active regions as they progressed across the solar disk, analyzing the correlation between the SOLIS measurements and the LOS magnetic field at various heights in the NLFFF data cubes. We examined the dependence of these heights on latitude, longitude, distance from the solar center, resolution of the model, and different solar features. Although our investigation did not produce precise heights for use in future modeling efforts, we discovered a systematic mismatch between the SOLIS weak-field approximation and the NLFFF extrapolations, which suggests that accurate heights could be identified after a revaluation of the SOLIS data calibration. |
Saturday, November 10, 2018 5:24PM - 5:36PM |
G02.00006: On the Origin of the Slow Solar Wind Joseph Luc B Robitaille, Pierre-Marie L Robitaille It has been recently advanced that the body of the Sun is comprised of liquid metallic hydrogen with a hexagonal planar lattice structure at the level of the photosphere (P.M. Robitaille, Progr. Phys. 2013, 4, 90-142). The chromosphere and corona are thought to include dense hydrogen, metallic hydrogen, and gaseous plasma. Recent evidence reveals that the corona is highly structured and fragmented (C.E. DeForest et al., Astrophys. J. 2018, 862(1), 1-18), supporting the presence of condensed matter in this region. The production of slow solar winds can be explained by inferring large-scale sublimation and fragmentation of chromospheric and/or coronal condensed matter. This breakdown of condensed matter explains both the structured and fragmented appearance of the corona, and the production of the slow solar wind as hydrogen gas produced by the phase change begins to expand. This is a simple process involving chemical principles. It does not involve the heating of coronal gas by magnetic fields to drive expansion at the corona, as currently believed. Concerning the fast solar wind, this process is likely due to the expulsion of intercalate atoms from the solar body as previously discussed (J.C. Robitaille and P.M. Robitaille, Progr. Phys. 2013, v. 2, 87-97). |
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