12-20 July 2017
BEXCO
Asia/Seoul timezone
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SH(Solar and heliospheric phenomena)

Place

Location: BEXCO
Address: BUSAN, KOREA
Date: from 14 Jul 13:30 to 20 Jul 14:45

Conveners

  • 20 Jul 14:00 - 14:45
    • Ruffolo, David

Timetable | Contribution List

Displaying 57 contributions out of 57
SH
on 20/7/2017 at 5:00
Solar activity was observed at its lowest level during 2006 to 2009, that is, since the beginning of the space exploration era. During this period, the PAMELA space experiment observed spectra for galactic cosmic rays, specifically for protons, electrons and positrons over a wide energy range, during what is called an A < 0 solar magnetic polarity cycle. Drift theory predicts a difference in behav ... More
Presented by Marius POTGIETER on 17/7/2017 at 4:45
A hybrid transport model is used for studying the modulation of galactic cosmic ray in the global heliosphere. This model incorporates the simulation data from a comprehensive MagnetoHydroDynamics (MHD) model with the traditional cosmic ray transport model, which solve the Parker’s transport equation using a Stochastic Differential Equations (SDE) approach. Since the MHD simulation data includes ... More
Presented by Xi LUO on 14/7/2017 at 4:45
Low-rigidity cosmic rays and solar particles are strongly deflected by Earth's geomagnetic field and only particles above a certain geomagnetic cutoff rigidity are able to reach space-based or balloon-borne experiments. Geomagnetic cutoff calculations utilizing the PLANETOCOSMICS software with the IGRF geomagnetic field and the Tsyganenko magnetosphere models are discussed. These calculations focu ... More
Presented by Philip VON DOETINCHEM on 17/7/2017 at 5:30
The cosmic rays originating outside the solar system are blocked by the Sun and form a shadow in the sky map, whose shape is affected by the magnetic field between the Sun and the Earth. Therefore the Sun shadow can be used as a probe of the magnetic field and its intensity variations. In this work, we report on the observation of the energy dependent variation of the Sun shadow signal in the ener ... More
Presented by Songzhan CHEN on 14/7/2017 at 7:30
Especially, in association with strong solar flares, we sometimes observe enhancements of visible continuum radiation, which is known as a ”white-light flare”. They are still only rarely observed since first being discovered more than 150 years ago, and origin of white-light emission is not still fully understood. Since most of white-light events show a close correlation in time profile and lo ... More
Presented by Kyoko WATANABE on 14/7/2017 at 9:00
Drift effects have long been known to play a significant role in the transport of charged particles in the heliosphere. A turbulent magnetic field is also known to reduce the effects of particle drifts. The exact nature of this reduction, however, is not clear. This study aims to provide some insight into this reduction, and proposes a relatively simple, tractable means of modelling it that provid ... More
Presented by Nicholas Eugene ENGELBRECHT on 14/7/2017 at 5:15
The charge-sign dependent modulation of cosmic rays is an important topic in solar modulation studies, providing insights into gradient, curvature, and current sheet drifts.  Such studies, at higher levels of solar activity, have always been associated with challenges due to the limitations of numerical modulation models. We employ a three-dimensional numerical model based on stochastic different ... More
Presented by Jan-Louis RAATH on 14/7/2017 at 5:30
The pitch-angle distributions of solar energetic particles (SEPs) provide a wealth of information about particle transport through interplanetary space, and can depend on the magnetic field strength, topology, and turbulence at remote heliospheric locations. The Low Energy Telescope (LET) on STEREO measures angular distributions in the ecliptic for SEP ions from protons to iron with energies of ab ... More
Presented by Richard LESKE on 15/7/2017 at 5:45
The solar cycle 23 provided several strong ground level enhancements (GLEs). The first strong GLE event was observed on 14 July 2000 (the Bastille day event), while the last was observed on 13 December 2006. In addition, the period of late October - early November 2003 was characterized by a strong cosmic ray variability and a sequence of three GLEs, registered by the worldwide neutron monitor net ... More
Presented by Aleksandar MISHEV on 15/7/2017 at 8:30
The purpose of this investigation is establish eleven year variation in cosmic ray intensity particularly in third harmonic after using cosmic ray intensity neutron monitor data on sixty quiet days. It has been observed that in spite of abrupt variation in amplitude and phase of third harmonic of cosmic ray intensity, the amplitude of third harmonic is relatively larger during the declining phase ... More
Presented by Mahendra Kumar RICHHARIA on 18/7/2017 at 5:30
The GRAPES-3, a large muon tracking detector experiment in India, reported recently a short "burst" of cosmic ray intensity observed lasting about one hour in June 22, 2015 in association with a large geomagnetic storm following the arrival of an interplanetary shock at the Earth (Mohanty et al., Physical Review Lett., 117, 2016). In the present paper, we analyze this event observed with the Globa ... More
Presented by Kazuoki MUNAKATA
Neutron monitors (NMs) are the premier instruments for precisely tracking time variations in the Galactic cosmic ray (GCR) flux at the GV-range. The worldwide NM network has provided continuous measurements of the solar induced variations of the GCR flux impinging Earth and the data cover about six 11-year solar cycles. The recent rise of space exploration, with PAMELA and AMS-02 spacecraft, bring ... More
Presented by Pierre-Simon MANGEARD on 18/7/2017 at 8:15
Understanding the modulation of Galactic and Jovian electrons, and Galactic positrons, in the heliosphere has become even more important with the availability of precise measurements of these cosmic ray species near the Earth and for electrons out to the heliopause. Comprehensive numerical models are used to investigate the main modulation features of these particles, including particle drifts and ... More
Presented by Donald NGOBENI on 17/7/2017 at 8:45
In this work we use modulation model based on the numerical solution of Parker's transport equations to study the galactic cosmic rays (GCRs) modulation in the inner heliosphere varying with solar cycles. We use the non-linear quasi-linear diffusion theory with a model to describe the magnetic turbulence throughout the heliosphere.  It is shown that the turbulence model agrees well w ... More
Presented by Gang QIN on 14/7/2017 at 5:45
During periods of elevated solar activity, solar energetic particles (SEPs) accelerated at the Sun in eruptive events (flares and coronal mass ejections) constitute the main source of energetic particles in the heliosphere. A pool of suprathermal particles can form from high-energy SEPs, accelerated during prior and ongoing solar and interplanetary activity that lose energy via adiabatic decelerat ... More
Presented by George HO on 15/7/2017 at 5:30
We fit the 0.1-500 MeV/nucleon H-Fe spectra in 46 large SEP events observed at 1 AU with the double power-law Band function to obtain a normalization constant, low- and high-energy parameters parameters $gamma_{a}$ and $gamma_{b}$, and break energy $E_B$, and derive the low-energy spectral slope $gamma_{1}$. We find that: 1) $gamma_{a}$, $gamma_{1}$, and $gamma_{b}$ are species-independent and the ... More
Presented by Mihir DESAI on 15/7/2017 at 4:45
We present results of the analysis of experimental data obtained by the set of cosmic ray and electric field instruments installed at CASLEO (San Juan, Argentina) since 2006. Considreation is focused on the events related to the variations of the surface electric field and associated cosmic ray variations recorded in 2016. We present results of comparative analysis of available solar, interplaneta ... More
Presented by Vladimir MAKHMUTOV
At the 33rd ICRC, we reported the possible detection of solar gamma rays by a ground level detector and later re-examined this event. On March 7, 2011, the solar neutron telescope (SNT) located at Mt. Sierra Negra, Mexico (4,600 m) observed enhancements of the counting rate from 19:49 to 20:02 UT and from 20:50 to 21:01 UT. The statistical significance was 9.7σ and 8.5σ, respectively. This paper ... More
Presented by Yasushi MURAKI on 14/7/2017 at 8:30
We simulate trajectories of energetic particles from impulsive solar flares for 2D+slab models of magnetic turbulence in spherical geometry to study dropout features, i.e., sharp, repeated changes in the particle density. Among random-phase realizations of two-dimensional (2D) turbulence, a spherical harmonic expansion can generate homogeneous turbulence over a sphere, but a 2D fast Fourier transf ... More
Presented by David RUFFOLO on 17/7/2017 at 7:45
By analyzing the Sun's shadow in the multi-TeV cosmic-ray intensity observed with the Tibet-III air shower array since 2000, we find a clear solar cycle variation of the deficit intensity in the shadow in a correlation with the solar activity, which has been first found in ~10 TeV cosmic ray intensity observed with the Tibet-II array. We find furthermore that the MC simulations of the Sun's shadow ... More
Presented by Kazumasa KAWATA on 14/7/2017 at 7:45
Ground Level Enhancements (GLEs) are a particular class of solar energetic particle (SEP) events in which the particle spectrum is hard enough to produce effects on the Earth’s surface. Historically a GLE had to be observed by two separate ground-based monitors to be added to the informal ‘GLE list’ (http://neutronm.bartol.udel.edu/~pyle/GLE_List.txt). As these events are among the most ener ... More
Presented by Christina COHEN on 15/7/2017 at 8:15
We study the long-term change of the amplitude of the first (27-day, A27) and second (14-day, A14) harmonics of the galactic cosmic rays (GCR) recurrent variation connected to the solar rotation period. Using two high-latitude neutron monitors, Oulu and Apatity, we verify the dominant 11-year cycle in A27 and A14 and their systematic 22-year variation (Hale cycle) during sunspot minima, with highe ... More
Presented by Agnieszka GIL on 17/7/2017 at 5:15
Two calibration neutron monitors were built in the beginning of this century to calibrate the worldwide neutron monitors. Since 2011, the idea changed to mini neutron monitors that can be used in their own right, with updated new electronics. During 2016 the electronics head were redesigned to be completely modular, as cheap as possible, but still reliable, and in such a way that they can also be ... More
Presented by Helena KRUGER on 18/7/2017 at 8:45
On 2017 January 18, scaler rates in the IceTop detectors at the South Pole revealed an impulsive increase in the galactic cosmic ray flux lasting a few hours. In addition to the neutron monitor at Pole the event was detected clearly by the Mawson neutron monitor and faintly at Jang Bogo. No other neutron monitors appear to have seen the increase. The event was in many ways reminiscent of the 2015 ... More
Presented by Paul EVENSON on 17/7/2017 at 8:00
To investigate the dependence of large gradual solar energetic particle (SEP) events on the associated flares, the correlation coefficients between the peak intensities of E>0 MeV, E>30 MeV and E>50 MeV protons and the fluence of associated solar soft X-ray (SXR) emission in the three longitudinal areas W0-W39, W40-W70 and W71- W90 have been calculated respectively. The derived correlation coeffic ... More
Presented by Guiming LE on 14/7/2017 at 9:15
The Latin American Giant Observatory (LAGO) is a widespread cosmic ray observatory which uses Water Cherenkov Detectors (WCD) deployed in nine Latin American countries, being able to detect transient events or long-term modulation effects simultaneously at places having different geomagnetic rigidity cut-offs and altitudes. In this work results of studies on cosmic ray muon flux variations during ... More
Presented by Anderson Campos FAUTH
This work investigates the spatial and temporal invariance in the spectra of energetic particles in gradual solar events. In the ecliptic at 1 AU, the time profiles of particle fluxes with different energies are calculated in simulations. According to simulation results, we find that shock acceleration strength, parallel diffusion, and adiabatic cooling are the main factors in forming the spatial ... More
Presented by Anderson Campos FAUTH on 15/7/2017 at 5:15
The HAWC Gamma Ray observatory consists of 300 water Cherenkov detectors (WCD) instrumented with four photo multipliers tubes (PMT) per WCD. HAWC is located between two of the highest mountains in Mexico. The high altitude (4100 m asl); the relatively short distance to the Gulf of Mexico (~100 km); the large detecting area (22 000 square m) and the high sensitivity, make HAWC a very good instrumen ... More
Presented by Alejandro LARA on 18/7/2017 at 5:15
The angler displacement between the center of the sun's shadow and the center of the optical solar disc tells us the information of average solar magnetic field strength from the solar to the earth. We analyze the Sun's shadow observed in 5 ~ 240 TeV cosmic-ray intensity with the Tibet air shower array during 10 years between 2000 and 2009, and make MC simulation data of the sun’s shadow based o ... More
Presented by Yoshiaki NAKAMURA on 14/7/2017 at 8:00
The era of direct or indirect (ground-based) observations of solar energetic particle (SEP) events covers forty and 70-80 years, respectively. While thousands of soft-spectrum SEP events have been recorded directly in space, only about 70 hard-spectrum events detectable at the ground-level (called GLE -- ground-level enhancements) have been identified, the greatest being GLE #5 on 23-Feb-1956. Yet ... More
Presented by Ilya USOSKIN on 15/7/2017 at 8:00
The worldwide network of neutron monitors (NMs) includes two stations, South Pole (SOPO/B) and Dome C (DOMC/B), which are exceptionally sensitive to solar energetic particles. Their locations on the Antarctic plateau make them favorable for detection of low-energy particles because of the low geomagnetic rigidity cutoff and the thin atmosphere above. This pair of cosmic ray stations is able to reg ... More
Presented by Stepan POLUIANOV on 15/7/2017 at 7:45
A model of Forbush decrease in a magnetic cloud is presented. We calculate moments of the particle distribution function depending on time. The calculated results of cosmic ray intensity generally agree with the observed ones in events registered by ground based detectors. It is found that the magnetic flux rope is of great importance in dynamics of Forbush decrease.
Presented by Anastasia PETUKHOVA on 17/7/2017 at 8:30
A simplified ab initio approach is followed to model cosmic-ray modulation using a steady-state three-dimensional stochastic solver of the Parker transport equation. Standard diffusion coefficients based on Quasilinear Theory (QLT) and Nonlinear Guiding Center Theory (NLGC) are used. The spatial dependencies of turbulence quantities required as input for the drift and diffusion coefficients follow ... More
Presented by Katlego MOLOTO on 17/7/2017 at 9:00
During the first 5 years of operations on board of the International Space Station, from May 2011 to May 2016, AMS has detected sudden reductions of the cosmic ray intensity —the so-called Forbush decrease events. The method used to identify the reductions of the proton flux is described. For the first time, the detailed time evolution of selected events is presented in different rigidity bins. ... More
Presented by Matteo PALERMO on 17/7/2017 at 8:15
The number of large solar energetic particle (SEP) events in solar cycle 24 is reduced by a factor of about 2 compared to cycle 23. In the first 8 years of this cycle there have been only 38 “GOES” greater than 10 MeV proton events, compared to 79 at this point of cycle 23. What is less well known is that the fluence of protons and heavier ions is reduced by even greater factors (by 6 times fo ... More
Presented by Richard MEWALDT on 15/7/2017 at 7:30
On the basis of data of Nagoya multi-directional muon telescope the long-term variations of vector and tensor anisotropies of cosmic rays that was registered in the period 1971-2015 are investigated. Decomposition of observed diurnal anisotropy into vector and tensor components is held using the method of receiving vectors. It is shown, that: 1. the amplitude of vector anisotropy reveals 11-year v ... More
Presented by Petr GOLOLOBOV on 18/7/2017 at 7:45
The temporal variations of the galactic cosmic ray (GCR) protons and antiprotons, measured by BESS, covering solar minimum, solar maximum, and solar magnetic field reversal, provide a crucial test of the charge-sign dependence of solar modulation. Here we develop a numerical model based on the stochastic differential equations equivalent to the Parker transport equation to study the charge-sign de ... More
Presented by Shoko MIYAKE on 17/7/2017 at 5:00
Voyager 2 (V2) has been observing anomalous cosmic rays (ACRs) in the heliosheath since August 2007 when V2 crossed the termination shock of the supersonic solar wind. The anisotropy of the counting rate of ~0.5-35 MeV protons is determined during periods when the spacecraft was rolling about the axis pointed toward Earth. The derived flow velocity is the combination of the convective flow due to ... More
Presented by Edward STONE on 14/7/2017 at 4:30
Cosmogenic nuclide Be-7 having the half-life of 53 days is a useful tool to investigate relationships between solar activities and low energy cosmic rays, because it is produced in the upper atmosphere through the spallation reaction of air elements due to the secondary cosmic rays, with the threshold energy of 10 MeV. Since the Be-7 is quickly oxidized and then descends to the ground attaching to ... More
Presented by Soichiro SUZUKI on 18/7/2017 at 4:45
Solar neutron telescopes (SNT) were designed and installed on high mountains to study particle acceleration mechanisms in solar surface. Of these, SciBar cosmic ray telescope (SciCRT) is a brand new telescope installed on the top of the Sierra Negra volcano in eastern Mexico (19.0 N,97.3 W) composed of roughly 15000 scintillator bars, capable of detecting solar particles with both high efficiency ... More
Presented by Marcos ANZORENA on 18/7/2017 at 9:00
Observations show that there are proton spectral ``breaks" with energy E$_{br}$ at 1-10MeV in some large solar energetic particle (SEP) events. Generally, single CME-driven shock applying diffusive acceleration mechanism would just predict a single power law energy spectrum. This work focuses on the difference of the energy spectra between a single shock and the converging double-shock. We apply a ... More
Presented by Xin WANG on 15/7/2017 at 5:00
The SciBar Cosmic Ray Telescope (SciCRT) is aimed at elucidating the acceleration mechanism of high-energy ions that may produce neutrons at the Sun. This is a fully active scintillator tracker which consists of 14,848 plastic scintillator bars, originally constructed for accelerator neutrino oscillation experiments. The SciCRT has a huge detector volume compared with conventional Solar Neutron Te ... More
Presented by Yoshinori SASAI on 14/7/2017 at 8:15
Propagation of energetic particles through magnetized turbulent media is reconsidered using the exact solution of Fokker-Planck equation. Shortfalls in the current cosmic ray (CR) transport models obscure the CR sources and acceleration mechanisms. This problem became particularly evident after the Fermi, Pamela, and AMS-02 have discovered the electron/positron and p/He spectral anomalies. Most of ... More
Presented by Mikhail MALKOV on 17/7/2017 at 7:30
High-energy and sustained emission from Long Duration Gamma-Ray Flares (LDGRFs), identified with Compton Gamma-Ray Observatory (CGRO), the Solar Maximum Mission (SMM), and now Fermi, has been a challenge to explain. The highest energy emission has generally been attributed to pion production from the interaction of high-energy protons with the ambient matter, suggesting that particle acceleration ... More
Presented by Eric CHRISTIAN on 14/7/2017 at 8:45
Variations in the space radiation environment due to changes in the GCR (Galactic Cosmic Ray) from the past (# 23) solar cycle to the current one (# 24) has been intriguing in many ways, with an unprecedented long duration of the recent solar minimum condition and a very low peak activity of the current solar maximum. Model calculated radiation data and assessment of variations in the particle flu ... More
Presented by Premkumar SAGANTI on 15/7/2017 at 8:45
The satellite-borne PAMELA experiment was launched on the 15th June 2006 from the Baikonur cosmodrome. Till January 2016 PAMELA has detected the charged component of cosmic-rays over a wide energy range. Due to its long flight duration PAMELA represents an ideal detector for cosmic-ray solar modulation studies. Moreover, the capability to measure particles of the same mass with opposite charge all ... More
Presented by Riccardo MUNINI on 17/7/2017 at 4:30
The Princess Sirindhorn Neutron Monitor (PSNM) is an 18NM64 (with 18 counter tubes in a continuous row) at 2560 m altitude in Doi Inthanon, Thailand. In late 2015, the electronics in the PSNM were upgraded so as to return an absolute time, referenced to the GPS time, for each neutron count recorded. The timing accuracy is approximately +/- 3 microseconds. This permits extending the well-known conc ... More
Presented by Alejandro SÁIZ on 18/7/2017 at 8:30
The effect of thunderstorm electric field on the muon intensity was observed for the first time in the experiment studying variations of cosmic rays at the Baksan Neutrino Observatory. It was demonstrated that the muon flux as a function of near-ground electric field could be represented by a second order polynomial in a rather wide range of field strengths (± 7 kV per meter). This curve is very ... More
Presented by Alexander LIDVANSKY on 18/7/2017 at 5:00
The large area (560 m^2) GRAPES-3 tracking muon telescope in Ooty, India recorded a 2 hour muon burst on 22 June 2015 starting at 19:00 UT in the midst of a continuing Forbush decrease. The burst occurred following the arrival of a coronal mass ejection containing a 40 nT south-ward interplanetary magnetic field (IMF) that had triggered a G4 class geomagnetic storm. During the 2 hour, the muon tel ... More
Presented by P.K. MOHANTY on 15/7/2017 at 9:15
We discuss the very important problem of the climate changes and consider the role of charged particle fluxes in this process. There is the correlation between the changes of global temperature near the ground level and charged particle fluxes in the lower atmosphere (altitudes up to 2.5 km). The data on charged particle fluxes were obtained in our atmospheric experiments. The mechanism responsibl ... More
Presented by Yuri STOZHKOV on 18/7/2017 at 4:30
Ab initio cosmic-ray modulation models require turbulence spectra as input for the diffusion tensor. If one assumes a composite slab/2D structure for the turbulence, the so-called slab ratio, which is the ratio of the energy density in the slab spectrum compared with the total energy density is required. Bieber et al. (1996, JGR, 101) describe two methods for calculating this ratio; Saur and Biebe ... More
Presented by Renier BURGER on 18/7/2017 at 8:00
Beside obvious similarities, the temporal and spatial variation of galactic cosmic rays (GCRs) are known to have distinct differences in even and odd 11-year solar cycles. These differences are attributed to particle drifts which are sensitive to the polarity of the large scale magnetic field of the Sun. An important and remarkable role is played by the structure of the heliospheric current sheet ... More
Presented by Jozsef KOTA on 14/7/2017 at 5:00
We study features of the three dimensional (3D) galactic cosmic ray (GCR) solar anisotropy for 1965-2017 (almost 5 solar cycles 20-24). We reveal periodic oscillations connected with the rotation of the Sun (~ 27 days). We analyze the first (~27 days), second (~13 days) and third (~9 days) harmonics of the 27-day variation of the (1) two dimensional (2D) GCR anisotropy in the ecliptic plane, and ( ... More
Presented by Renata MODZELEWSKA on 18/7/2017 at 7:30
In the last years became possible to have on-line through Internet one-minute cosmic ray (CR) data from many neutron monitors and muon telescopes (in high energy region) as well as from several spacecrafts (in very low energy region). To avoid damage of electronics and negative effects for people health is necessary on-line forecast expected fluency of energetic particles and radiation hazards. It ... More
Presented by Lev DORMAN on 15/7/2017 at 9:00
The charged particle acceleration and transport during solar events have been widely studied in the past decades. The satellite-borne PAMELA experiment has been continuously collecting data since 2006. The apparatus is designed to study charged particles in the cosmic radiation. The combination of permanent magnet, silicon micro-strip spectrometer and silicon-tungsten imaging calorimeter, with the ... More
Presented by Matteo MERGÈ on 15/7/2017 at 4:30
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