I investigate the processes at work in the cancellation of normal magnetic flux in solar magnetograms and study the relationships between cancellation and the budget of free magnetic energy in the coronal magnetic field that can power solar flares and CMEs. After defining cancellation mathematically, I derive equations that quantify the evolution of free magnetic energy in response to arbitrary...

This paper updates the influence of environmental and source factors of shocks driven by coronal mass ejections (CMEs) that are likely to influence the solar energetic particle (SEP) events. The intensity variation due to CME interaction reported in [1] is confirmed by expanding the investigation to all the large SEP events of solar cycle 23. The large SEP events are separated into two groups, ...

An observational relationship has been well established among magnetic reconnection, high-energy flare emissions and the rising motion of erupting flux ropes. In this paper, we verify that the rate of magnetic reconnection in the low corona is temporally correlated with the evolution of flare nonthermal emissions in hard X-rays and microwaves, all reaching their peak values during the rising ph...

The main objective of the SunFlare project is modelling and understanding the couplings between the sub-surface layers and visible layers of the Sun: the solar photosphere, chromosphere and corona. – The mass density is much larger in the subsurface layers than in the visible layers. The kinetic and magnetic energy densities are also correspondingly large. The motions that occur in these layers...

A statistical analysis of coronal loop oscillations observed by TRACE shows that 12 of 28 cases were associated with metric type II bursts. The timing is consistent with the idea that the loop oscillations in many cases result from the passage of a large-scale wave disturbance originating in a flare in the nearby active region. The GOES classifications for these flares range from C4.2 to X20. T...

More and more evidence indicates that “EIT waves” are strongly related to coronal mass ejections (CMEs). However, it is still not clear how the two phenomena are related to each other. We investigate a CME event on 1997 September 9, which was well observed by both EUV imaging telescope (EIT) and the high-cadence MK3 coronagraph at Mauna Loa Solar Observatory, and compare the spatial relation be...

Solar mini-dimmings can be detect in the Extreme Ultra-Violet coronal eruptions. Here, sequences of 171_A images taken by Solar Dynamic Observatory/Atmospheric Imaging Assembaly on 13 June 2010 are used. In this special day, both of coronal mass ejection and prominence were observed. The average velocities and accelerations of 500 mini-dimmings which were detected using on feature based classif...

Two Earth-directed coronal mass ejections (CMEs), which were most e€ective in energetic ($1± 50 MeV) particle acceleration during the ®rst 18 months since the Solar and Heliospheric Observatory (SOHO) launch, occurred on April 7 and May 12, 1997. In the analysis of these events we have deconvoluted the injection spectrum of energetic protons by using the method described by Anttila et al. In or...

We analyse the evolution of a sigmoidal (S shaped) active region toward eruption, which includes a coronal mass ejection (CME) but leaves part of the filament in place. The X-ray sigmoid is found to trace out three different magnetic topologies in succession: a highly sheared arcade of coronal loops in its long-lived phase, a bald-patch separatrix surface (BPSS) in the hours before the CME, and...

Abstract A coronal mass ejection (CME) is an impulsive event that emerges rapidly from the Sun. We observed a quiet Sun without many spectacular episodes during last decade. Although some fast halo and partial CMEs had taken place, among them was backside CME on 23 July 2012. In this work, we verify link between variability of solar-wind, heliospheric geomagnetic parameters transmission grid fa...