tokens: show a decrease in the distance between conjugate footpoints (Figure 10 ). The converging motion of flare ribbons is confirmed by some recent observations (Ji et al. 2006 , 2007 ; Liu et al. 2008 ; Joshi et al. 2009 ) and, thus, it has been identified as an important phenomenon occurring during the rise phase of flares. In particular, Liu et al. ( 2008 ) noted that during SOL2002-04-30, the two conjugate HXR footpoints first move toward and then away from each other, mainly parallel and perpendicular to the magnetic inversion line, respectively. Furthermore, the transition between these two phases of footpoint motions coincides with the reversal in direction of the motion of the looptop source. The explanation of ribbon motions of this kind is still beyond the scope of the standard flare model. After a prolonged rise phase, the flare exhibited the features of a “standard” large eruptive flare as described by the standard flare model. Here the main observational characteristic of the standard flare is recognized in the form of an increase in the separation of parallel flare ribbons while they move perpendicular to the PIL (Figure 11 ). Following the eruption of the flux rope, we observed the development of an arcade of coronal loops over the source region that was previously occupied by the coronal sigmoid. This phenomenon, called sigmoid-to-arcade transformation, is well established and theoretically studied in relation to the eruptive dynamics of CMEs (Gibson et al. 2002 , 2004 ). In the radio spectrum, the violent eruption of the flux ropes is followed by the occurrence of a broad, intense type II radio burst, implying the propagation of a shock wave associated with the passage of the CME (see, e.g., Cho et al. 2005 ). We, therefore, conclude that the standard flare model is well applicable to the late phase of this flare. We believe that, during this phase, the main driver of the energy release process is the large-scale magnetic reconnection driven by the erupting FR. 5. CONCLUSIONS Sigmoid-to-arcade development is considered to be an important aspect of solar eruptive phenomena. Although the association of sigmoids with eruptions is well recognized, our knowledge about the formation of these structures and their subsequent activation is still limited. In this paper, we provide a comprehensive multi-wavelength investigation of EUV, UV, H α , X-ray, radio, and magnetic measurements to probe the evolution of a transient coronal sigmoid in active region NOAA 11719, which activates and erupts, leading to a fast halo CME. In the following, we summarize the important results of this study: 1. The observations of the active region in the hot EUV channel of AIA (94 Å) reveal the formation of a large S-shaped FR through a sequence of multiple, localized brightenings involving two large pre-existing coronal loop systems. Considering the fact that the bright emission in 94 Å images corresponds to hot plasma ( T ∼ 6 MK), we attribute the multiple
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