نتایج جستجو برای: solar flares
تعداد نتایج: 123758 فیلتر نتایج به سال:
Superflares are large explosive events on stellar surfaces one to six orders-of-magnitude larger than the largest flares observed on the Sun throughout the space age. Due to the huge amount of energy released in these superflares, it has been speculated if the underlying mechanism is the same as for solar flares, which are caused by magnetic reconnection in the solar corona. Here, we analyse ob...
Aims. In this work we study the correlation between the soft (1.6–12.4 keV, mostly thermal) and the hard (20–40 and 60–80 keV, mostly non-thermal) X-ray emission in solar flares up to the most energetic events, spanning about 4 orders of magnitude in peak flux, establishing a general scaling law and extending it to the most intense stellar flaring events observed to date. Methods. We used the d...
We address in detail the cellular automaton approach, developed for the case of solar flares, and compare it to the magnetohydrodynamic (MHD) theory. We consider solar flares as typical complex dynamical systems and we are interested in their global dynamical behavior, through their statistical properties.
Magnetic reconnection is a process of magnetic field topology change, which is one of the most fundamental processes happening in magnetized plasmas. In most astrophysical environments, the Reynolds numbers corresponding to plasma flows are large and therefore the transition to turbulence is inevitable. This turbulence, which can be pre-existing or driven by magnetic reconnection itself, must b...
The driving mechanism of solar flares and coronal mass ejections is a topic of ongoing debate, apart from the consensus that magnetic reconnection plays a key role during the impulsive process. While present solar research mostly depends on observations and theoretical models, laboratory experiments based on high-energy density facilities provide the third method for quantitatively comparing as...
It has been proposed that flares in the solar corona may well be a result of an internal self-organized critical (SOC) process in active regions. We have developed a cellular automaton SOC model that simulates flaring activity extending over an active subflaring background. In the resulting frequency distributions we obtain two distinct power laws. That of the weaker events is shorter and much ...
Context. Modern solar X-ray imagers did not breakthrough the problem of detailed diagnostics of faint hard X-ray sources in the presence of stronger ones. This is the case of the impulsive phase of solar flares in which footpoint sources are usually stronger than loop-top ones. Aims. For this aim, flares being partially occulted by the solar limb, are the best reservoir of our knowledge about h...
Currently, astronomical data have increased in terms of volume and complexity. To bring out the information in order to analyze and predict, the artificial intelligence techniques are required. This paper aims to apply artificial intelligence techniques to predict M-class solar flare. Artificial neural network, support vector machine and naïve bayes techniques are compared to define the best pr...
The study of the statistical distribution of the quiescent times between solar flares has been investigated on a 1D MHD model. The result shows a power law behaviour in agreement with the observations. This strong time correlation of flares is different from the SOC prediction unless overlap of events is allowed. Many observations e.g. Skylab, SMM, Yohkoh, GRANAT, SoHO or TRACE have shown the m...
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