Search Publications
Cosmic Ray Modulation with the Maximum CME Speed Index During Solar Cycles 23 and 24
Kilcik, Ali; Sarp, Volkan; Yurchyshyn, Vasyl +2 more
We analyzed modulation of cosmic-ray intensities (CRIs) during Solar Cycles 23 and 24 by using the international sunspot numbers (ISSN) and the maximum CME speed index (MCMESI) as proxies for solar activity. Temporal variations, cross-correlations, and hysteresis patterns of CRI, MCMESI, and ISSN data were investigated. As a result, we concluded t…
Association of Calcium Network Bright Points with Underneath Photospheric Magnetic Patches
Pant, Vaibhav; Banerjee, Dipankar; Narang, Nancy +1 more
Recent dedicated Hinode polar region campaigns revealed the presence of concentrated kilogauss patches of the magnetic field in the polar regions of the Sun, which are also shown to be correlated with facular bright points at the photospheric level. In this work, we demonstrate that this spatial intermittency of the magnetic field persists even up…
Comparative Study of Microwave Polar Brightening, Coronal Holes, and Solar Wind over the Solar Poles
Masuda, Satoshi; Yashiro, Seiji; Shibasaki, Kiyoto +3 more
We compared the long-term variation (1992 - 2017) in solar polar brightening observed with the Nobeyama Radioheliograph, the polar solar-wind velocity with interplanetary scintillation observations at the Institute for Space-Earth Environmental Research, and the coronal-hole distribution computed by potential-field calculations of the solar corona…
Characteristics of SEP Events and Their Solar Origin During the Evolution of Active Region NOAA 10069
Myagkova, I. N.; Kashapova, L. K.; Miteva, R. +1 more
We present the results of a comparative analysis of the properties of a series of successive solar flares, which occurred in active region (AR) 10069 in August 2002, and the associated solar energetic particle (SEP) events. The active region was extremely flare productive during its evolution. The solar flare characteristics are based on X-ray and…
Velocity Structure and Temperature Dependence of an Extreme-Ultraviolet Jet Observed by Hinode
Imada, S.; Kawai, T.; Kanda, N.
The acceleration mechanism of EUV and X-ray jets is still unclear. In general, there are two candidates for the mechanism. One is magnetic reconnection, and the other is chromospheric evaporation. We observed a relatively compact X-ray jet that occurred between 10:50 - 11:10 UT on 18 February 2011 by using the Solar Dynamics Observatory/Atmospheri…
Transient Dimming of the Bright Fe XIV Emission Region in the Solar Corona of the 21 August 2017 Total Solar Eclipse
Liebenberg, D. H.
During the 21 August 2017 total solar eclipse the corona was observed through a narrowband filter centered at the Fe XIV green emission line at a cadence of 30 frames/s. A bright region on the east limb was observed to dim during the 2 m 35 s totality. Details of the temporal behavior of this region are reported. The likely association of the dimm…
Quiet-Sun EUV He II (30.4 nm) Spatial Power Ratios and Network Dissipation Trend for 2010 - 2018
Didkovsky, Leonid
We explore a significant change of the trend of the transition region network scale variation that occurred around of 2016 when a series of spotless days in 2018, with similar radiative characteristics, were added to previously analyzed days in 2017. We find that a mean per six-year spatial power ratio for 2016 vs. 2010 shows a 29% yearly increase…