Observational evidence for breakout reconnection

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In solar eruptive events (SEE)'s the transition from slow to fast (eruptive) energy release leads to the interaction of a flux rope with the overlying magnetic field. If the flux rope has a field component opposite to that of the overlying field, magnetic reconnection between both fields can be observable due to the associated electron acceleration and radio emission. Such a breakout reconnection scenario is included in many numerical simulations of SEEs, but observational support for it has so far been weak.   
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In solar eruptive events (SEE)'s the transition from slow to fast (eruptive) energy release leads to the interaction of a flux rope with the overlying magnetic field. If the flux rope has a field component opposite to that of the overlying field, magnetic reconnection between both fields can become observable due to the associated electron acceleration and radio emission. Such a breakout reconnection scenario is included in many numerical simulations of SEEs, but observational support for it has so far been weak.   
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Strong evidence for breakout reconnection has recently been identified in the combined meter-wave radio and RHESSI X-ray observations of a well-observed SEE (Aurass et al. 2013). Figure 1 shows the dynamic radio spectrum (AIP) and the RHESSI 150-300 keV flux curve. The arrow indicates the onset of the impulsive flare phase. This onset phase of strong particle acceleration in the radio spectrum is enlarged in Figure 2 and depicts the instant shown in Figure 3: the radio images at two frequencies (Nançay Multifrequency Radioheliograph), as well as the hard X-ray images. 
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The two observed coronal X-ray sources serve to locate the two jets above and below the indicated flare reconnection site. Two radio sources are located radially above the X-ray sources. The upper of these two sources (here at NRH 432 MHz) is flanked by two sources (here shown at NRH 236.6 MHz) along a line perpendicular to the radially elongated X-ray and radio sources. 
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A plausible explanation for this arrangement is that the lower radio source, like the upper X‑ray source, was associated with the upward-directed flare reconnection jet. The upper radio above the flaring active region remained a stationary source indicating the ongoing breakout reconnection process.
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Strong evidence for breakout reconnection has recently been identified in the combined meter-wave radio and RHESSI X-ray observations of a well-observed SEE. Figure 1 shows the dynamic radio spectrum (AIP) and the RHESSI 150-300 keV flux curve. The arrow points on the time shown in Figure 1.  The two observed coronal X-ray sources serve to locate the two jets above and below the indicated flare reconnection site.  Two radio sources located radially above the X-ray sources are shown here as being representastive for the observations with the the AIP (Potsdam) Radiospectrograph and the Nançay Multifrequency Radioheliograph.  The upper of these two 432 MHz sources was flanked by two sources at 236 MHz along a line perpendicular to the radial line through the X-ray and 432 MHz sources. 
 
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The most plausible explanation for this arrangement is that the lower 432 MHz source, like the upper X‑ray source, was associated with the upward-directed flare reconnection jet. The upper 432 MHz source, which remained stationary, was associated with breakout reconnection ahead of the developing magnetic
 
Figure 1‑3. Scatter plot showing that the peak thermal energy is, on average, about an order of magnitude smaller than the time-integrated energy in flare-accelerated particles (Emslie et al. 2012).
Figure 1‑3. Scatter plot showing that the peak thermal energy is, on average, about an order of magnitude smaller than the time-integrated energy in flare-accelerated particles (Emslie et al. 2012).
flux rope.  The two 236 MHz sources would then naturally be associated with the roughly horizontal jets from the breakout reconnection well above the flaring active region.
flux rope.  The two 236 MHz sources would then naturally be associated with the roughly horizontal jets from the breakout reconnection well above the flaring active region.

Revision as of 10:59, 7 March 2013

In solar eruptive events (SEE)'s the transition from slow to fast (eruptive) energy release leads to the interaction of a flux rope with the overlying magnetic field. If the flux rope has a field component opposite to that of the overlying field, magnetic reconnection between both fields can become observable due to the associated electron acceleration and radio emission. Such a breakout reconnection scenario is included in many numerical simulations of SEEs, but observational support for it has so far been weak.

Strong evidence for breakout reconnection has recently been identified in the combined meter-wave radio and RHESSI X-ray observations of a well-observed SEE (Aurass et al. 2013). Figure 1 shows the dynamic radio spectrum (AIP) and the RHESSI 150-300 keV flux curve. The arrow indicates the onset of the impulsive flare phase. This onset phase of strong particle acceleration in the radio spectrum is enlarged in Figure 2 and depicts the instant shown in Figure 3: the radio images at two frequencies (Nançay Multifrequency Radioheliograph), as well as the hard X-ray images.

The two observed coronal X-ray sources serve to locate the two jets above and below the indicated flare reconnection site. Two radio sources are located radially above the X-ray sources. The upper of these two sources (here at NRH 432 MHz) is flanked by two sources (here shown at NRH 236.6 MHz) along a line perpendicular to the radially elongated X-ray and radio sources.

A plausible explanation for this arrangement is that the lower radio source, like the upper X‑ray source, was associated with the upward-directed flare reconnection jet. The upper radio above the flaring active region remained a stationary source indicating the ongoing breakout reconnection process.




Figure 1‑3. Scatter plot showing that the peak thermal energy is, on average, about an order of magnitude smaller than the time-integrated energy in flare-accelerated particles (Emslie et al. 2012). flux rope. The two 236 MHz sources would then naturally be associated with the roughly horizontal jets from the breakout reconnection well above the flaring active region.

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