The major goal of this project is to understand the physical mechanisms of solar energetic phenomena, namely CMEs (Coronal Mass Ejections) and flares, through comprehensive approaches. CMEs are large-scale eruptions of magnetized plasma traveling at speeds from hundreds to several thousand kilometers per second, hurdling a large amount of plasma and magnetic field into the space. Flares are transient release of energetic particles and thermal plasma, resulting in significant enhancement of electromagnetic radiation in almost all wavelengths from microwave to gamma rays. The physic of CMEs and flares involves energy storage in magnetic fields and electric currents, and in particular, the transient release of such energy in minutes. CMEs and flares are the known causes of severe space weather storms that affect the Earth space environment and compromise many advanced technological systems such as satellites, communication/navigation and electric power grids that are critical for society and life.

     The execution of this project has successfully obtained interesting scientific results that significantly advance our understanding of solar eruptions. We have examined almost all major solar flares (M and X GOES classes) from 1996 to 2013, covering the entire solar cycle 23^rd and the rising and maximum phases of solar cycle 24^th.  We find that about 57% major flares are eruptive, i.e., accompanied by CMEs. However, 43% major flares are confined or closed, not resulting in an open eruption. We further find that, the longer the flare rise time, the higher the possibility of eruption. We also find that, the longer the flare decay time, the faster the speed of the accompanying CMEs.  Extremely fast CMEs (speeds more than 1500 km/s) usually originate from large solar active regions that host strong and complex magnetic fields.   

       One major discovery of this project is the direct observation of magnetic flux ropes before the onset of CMEs and flares. Magnetic flux ropes are a special structure with magnetic field lines wrapping around a central axis, carrying a large amount of electric current and free magnetic energy. Scientists believe that magnetic flux rope is the core element in solar eruptions, but direct detection has been elusive. Thanks to high-qualify fast-cadence image sequences provided by Solar Dynamic Observatory spacecraft, the magnetic flux ropes for the first time are clearly visible as a twisted channel containing plasma of temperature as hot as 10 million degrees. Such hot temperatures of flux ropes have eluded their detection by earlier instruments that are sensitive to only cooler temperatures.  A magnetic flux rope has two legs rooted onto the surface, and continuously transform it from a sigmoidal shape to a semi-circular loop shape as it rises. We have studied morphological, kinematic and thermal dynamic evolutions of magnetic flux ropes. 

     On the theoretical aspect, we have investigated the stability and instability behavior of 3-D magnetic flux ropes.  We find that the evolution of magnetic flux ropes follows an analytic description, and the eruption is controlled by the so-called torus instability. We further find that there is a dependence of torus instability on the fractional parameter of the torus. A line-tying partial torus is more difficult to erupt than a full torus. This finding, validated through many observations, helps us understand the confinement, growth, and eventual eruption of CMEs.

     Besides publishing more than 20 refereed journal articles, numerous presentations in conferences and workshops and press releases,  the project has helped recruit and train many graduate students and two postdoctoral researchers. During the period ...

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