A new hypothesis of sunspot formation

Structure of proper motions in a sunspot penumbra

Was one sunspot cycle in the 18th century really lost?

The unusually long 4th solar cycle has recently been proposed by Usoskin et al. (2001) to be composed of two cycles. They argue that a weak and short cycle might have been lost in sparse sunspot data at the end of the 18th century. Here we check this hypothesis in different ways. First, we consider the sunspot number record in greater detail and compare in a statistical sense the sunspot observ...

A Comparative Study of New Identity Models in Western Asia

Current developments in western Asia suggest three new identity models have started to form and compete. Main inquiry of this article is to know what relation is there between these models. Hypothesis of the article proposes that through reproduction of the identity in an evolving process, each one of these identities has undertaken a role based on their historical identity and in a social grou...

A study on Ca II 854.2 nm emission in a sunspot umbra using a thin cloud model

In the present work, we introduce and explain a method of solution of the radiative transfer equation based on a thin cloud model. The efficiency of this method to retrieve dynamical chromospheric parameters from Stokes I profiles of Ca II 854.2 nm line showing spectral emission is investigated. The analyzed data were recorded with the Crisp Imaging Spectro-Polarimeter (CRISP) at Swedish 1-m So...

O ct 2 01 6 High resolution He I 10830 Å narrow - band imaging of an M - class flare . I - analysis of sunspot dynamics during flaring

In this paper, we report our first-step results of high resolution He i 10830 Å narrow-band imaging (bandpass: 0.5 Å) of an M1.8 class two-ribbon flare on July 5, 2012. The flare was observed with the 1.6 meter aperture New Solar Telescope at Big Bear Solar Observatory. For this unique data set, sunspot dynamics during flaring were analyzed for the first time. By directly imaging the upper chro...