TRACE and RHESSI observations of failed eruption of magnetic flux rope and oscillating coronal loops...
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Transcript of TRACE and RHESSI observations of failed eruption of magnetic flux rope and oscillating coronal loops...
TRACE and RHESSI observations of failed eruption of magnetic flux rope
and oscillating coronal loops
Tomasz MrozekAstronomical InstituteUniversity of Wrocław
The flare
M6.2 GOES classN14 W61
RHESSI: entire event
TRACE: 171 Å (several seconds
cadence)1600 Å (several cadence,
decay phase)
GOES SXI: several, saturated images
SOHO LASCO:no CME reported
The flare
GOES class M6.2 event connected with small (less than 104 km) arcade of loops.
Clearly associated with the eruption of the magnetic structure.
Evolution of the eruption
Initial phase connected with small brightenings in the HXRs
1Fast evolutionfollowing the strongest HXR peak visible in 25-50 keVrange
2
Deceleration phase. Main front changes its shape. Side eruptions areobserved
3
25-50 keV
H[k
m]
Higher in the corona…
Above the erupting structure we observed the system of loops.
These loops changes their height as the eruption evolves.
The shape of the eruption front shows that „something”stopped the ejection.
Side eruptions suggestthat such breaking does not take place on theboth sides of the high-lying loops
Interaction
High-lying loops started to rise
The end of the foremost eruption(and the end of the force driving the movement of the high-lying loops)
Oscillating loops
Oscillating loops
The same height before and after oscillations
Global oscillations of coronal loops
Radial, transversalChange of radius
One observation (Wang & Solanki 2004)
Tangential, horizontalNo change of radius
About 20 observations reported by several authors
14 Jul 2004 event
0
t
HetP
2sinA)t(H
Observed oscillations are well described with the use of dumped sine function.
Similar parameters to these obtained by Wang and Solanki (2004)
Using method describedby Nakariakov et al. (2001)we estimated magnetic field strength in the loop top to be equal 10-30 G
CONCLUSIONS
1. Interesting events happen in the Bastille Day (14 Jul).
2. Relatively strong flare was not associated with a CME due to failed eruption ofthe magnetic structure. Can be this a rule for old active regions with well developed, high-lying systems of loops?
3. The main agent of the deceleration was the magnetic tension of loops lying aboveerupting structure. Estimated magnetic field in the loop top is 10-30 G.
4. The second ever observation of radial oscillations of coronal loops was made. In this case we observed „the finger” that pulled loops – the magnetic structure ejected from below these loops.