M is for Magnifique Part Deux

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In this nugget, we continue our analysis of the M class flare of October 16th, 2010 ([http://sprg.ssl.berkeley.edu/~tohban/browser/?show=grts+qlpcr+qli02&date=20101016&time=191200 SOL2010-10-16T19:12]) which we have previously discussed in a [[M is for Magnifique|past nugget]].  In that nugget, we introduced AIA on SDO and discussed how SDO can be used to compliment RHESSI observations. We also pointed out a traveling disturbance propagating away from the flare site at great speeds.  In this nugget, we'd like to look a little closer at this phenomena and introduce some new tools to investigate similar behavior in the future.
In this nugget, we continue our analysis of the M class flare of October 16th, 2010 ([http://sprg.ssl.berkeley.edu/~tohban/browser/?show=grts+qlpcr+qli02&date=20101016&time=191200 SOL2010-10-16T19:12]) which we have previously discussed in a [[M is for Magnifique|past nugget]].  In that nugget, we introduced AIA on SDO and discussed how SDO can be used to compliment RHESSI observations. We also pointed out a traveling disturbance propagating away from the flare site at great speeds.  In this nugget, we'd like to look a little closer at this phenomena and introduce some new tools to investigate similar behavior in the future.
-
[[File:rhessi_goes_16_oct_2010.jpg|thumb|left|200px|'''Figure 0''': RHESSI and GOES lightcurves at select wavelengths during the 16th October 2010 flare.]]
+
[[File:rhessi_goes_16_oct_2010.jpg|thumb|left|200px|'''Figure 1''': RHESSI and GOES lightcurves at select wavelengths during the 16th October 2010 flare.]]
== Radio Waves ==
== Radio Waves ==
-
Radio observations are a sensitive method for observing accelerated electrons in the corona. Both flares and CMEs have their associated radio emission.  For flares, it is type III radio bursts which are thought to be the product of accelerated electrons escaping the solar corona.  They are observed as impulsive emission rapidly drifting to low frequencies (i.e. density) from high frequencies (i.e. density).  Type II radio bursts are thought to be associated with traveling shock waves and are therefore frequently associated with CMEs. They are observed as radio emission "slowly" drifting downward in frequency. Figure 1 shows the radio spectrum observed by the Green Bank Solar Radio Burst Spectrometer (GBSRBS). Both types of radio emission are observed here. Assuming a density model, it is possible to estimate the travel speed of type II producing shock. In this case, the travel speed was found to be approximately 950 km/s. This value matches well with the travel speed of the traveling disturbance observed by AIA as mentioned in the previous nugget. So perhaps, though other observatories (specifically coronagraphs) did not observe a CME, AIA did.
+
Radio observations are a sensitive method for observing accelerated electrons in the corona. Both flares and CMEs have their associated radio emission.  For flares, it is type III radio bursts which are thought to be the product of accelerated electrons escaping the solar corona.  They are observed as impulsive emission rapidly drifting to low frequencies (i.e. density) from high frequencies (i.e. density).  Type II radio bursts are thought to be associated with traveling shock waves and are therefore frequently associated with CMEs. They are observed as radio emission "slowly" drifting downward in frequency. Figure 2 shows the radio spectrum observed by the Green Bank Solar Radio Burst Spectrometer (GBSRBS). Both types of radio emission are observed here. Assuming a density model, it is possible to estimate the travel speed of type II producing shock. In this case, the travel speed was found to be approximately 950 km/s. This value matches well with the travel speed of the traveling disturbance observed by AIA as mentioned in the previous nugget. So perhaps, though other observatories (specifically coronagraphs) did not observe a CME, AIA did.
-
[[File:2010oct16_GBSRBSradio.png|thumb|center|600px|'''Figure 1''': The radio spectrum from the Green Bank Solar Radio Burst Spectrometer (GBSRBS) shows a set of type III radio bursts and type II radio bursts.  Type II radio bursts are signatures of traveling shock waves and are frequently associated with CMEs while Type III radio bursts are associated with escaping beams of accelerated electrons.  The speed of propagation of this particular type II burst is around 950 km/s. Note the dark shadow of the [http://en.wikipedia.org/wiki/Sudden_ionospheric_disturbance SID] (ionospheric absorption) below 10 MHz.]]
+
[[File:2010oct16_GBSRBSradio.png|thumb|center|600px|'''Figure 2''': The radio spectrum from the Green Bank Solar Radio Burst Spectrometer (GBSRBS) shows a set of type III radio bursts and type II radio bursts.  Type II radio bursts are signatures of traveling shock waves and are frequently associated with CMEs while Type III radio bursts are associated with escaping beams of accelerated electrons.  The speed of propagation of this particular type II burst is around 950 km/s. Note the dark shadow of the [http://en.wikipedia.org/wiki/Sudden_ionospheric_disturbance SID] (ionospheric absorption) below 10 MHz.]]
== Flare morphology ==
== Flare morphology ==
-
To the solar west of the main flare site a significant elongated structure is present in multiple wavelengths, including 171A and 304 A. The presence of this structure is made more interesting by the fact that it reacts to the eruption of the main flare.
+
To the solar west of the main flare site a significant elongated structure is present in multiple wavelengths, including 171A and 304 A, as shown in Figure 3. The presence of this structure is made more interesting by the fact that it reacts to the eruption of the main flare.
-
[[File:ribbon_171_304.jpg|thumb|right|600px|'''Figure Y''': An elongated ribbon structure to the solar west of the flare site, visible in 171 A and 304 A.]]
+
[[File:ribbon_171_304.jpg|thumb|right|600px|'''Figure 3''': An elongated ribbon structure to the solar west of the flare site, visible in 171 A and 304 A.]]
== Correlation maps ==
== Correlation maps ==
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In this way we create two types of map. First, a map showing the level of correlation for a particular lag, and secondly a map showing the lag corresponding to the maximum correlation. We can use this method as a qualitative measure of the propagation of a disturbance along the structure.
In this way we create two types of map. First, a map showing the level of correlation for a particular lag, and secondly a map showing the lag corresponding to the maximum correlation. We can use this method as a qualitative measure of the propagation of a disturbance along the structure.
-
We choose a master pixel located in the bottom-left corner of the ribbon structure. In multiple wavelengths, we can see the difference in the speed of propagation of heating along the structure as the energy from the main flare is deposited. In both 171 A and 304 A there is, on average, a considerable delay from the heating at the master pixel from the heating onset at the far end of the structure, a delay of over a minute for some pixels. However, it appears that the propagation of this disturbance is slower in the 304 A channel than in 171 A.
+
We choose a master pixel located in the bottom-left corner of the ribbon structure. In multiple wavelengths, we can see the difference in the speed of propagation of heating along the structure as the energy from the main flare is deposited. In both 171 A and 304 A there is, on average, a considerable delay from the heating at the master pixel from the heating onset at the far end of the structure, a delay of over a minute for some pixels (see Figure 4). However, it appears that the propagation of this disturbance is slower in the 304 A channel than in 171 A. In principle we can use this method to measure the different propagation speeds of plasma at different temperatures and parts of the atmosphere.
 +
 
 +
[[File:Nugget_maps.jpg|thumb|center|1000px|'''Figure 4''': Cross-correlation lag maps of AIA image cubes in the 171 A, 304 A and 1600 A bands.]]
-
[[File:Cor_map171.jpg|thumb|left|200px|'''Figure Za''': Cross-correlation lag map in the 171 A band.]]
 
-
[[File:Cor_map304.jpg|thumb|left|200px|'''Figure Zb''': Cross-correlation lag map in the 304 A band.]]
 
-
[[File:Cor_map1600.jpg|thumb|left|200px|'''Figure Zc''': Cross-correlation lag map in the 1600 A band.]]
 
== Conclusion ==
== Conclusion ==

Revision as of 19:42, 17 February 2011


Nugget
Number: 146
1st Author: Steven Christe
2nd Author: Andy Inglis
Published: 21 February 2011
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Previous Nugget: [At last, the EUV Spectrum]
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Contents

Introduction

In this nugget, we continue our analysis of the M class flare of October 16th, 2010 (SOL2010-10-16T19:12) which we have previously discussed in a past nugget. In that nugget, we introduced AIA on SDO and discussed how SDO can be used to compliment RHESSI observations. We also pointed out a traveling disturbance propagating away from the flare site at great speeds. In this nugget, we'd like to look a little closer at this phenomena and introduce some new tools to investigate similar behavior in the future.

Figure 1: RHESSI and GOES lightcurves at select wavelengths during the 16th October 2010 flare.

Radio Waves

Radio observations are a sensitive method for observing accelerated electrons in the corona. Both flares and CMEs have their associated radio emission. For flares, it is type III radio bursts which are thought to be the product of accelerated electrons escaping the solar corona. They are observed as impulsive emission rapidly drifting to low frequencies (i.e. density) from high frequencies (i.e. density). Type II radio bursts are thought to be associated with traveling shock waves and are therefore frequently associated with CMEs. They are observed as radio emission "slowly" drifting downward in frequency. Figure 2 shows the radio spectrum observed by the Green Bank Solar Radio Burst Spectrometer (GBSRBS). Both types of radio emission are observed here. Assuming a density model, it is possible to estimate the travel speed of type II producing shock. In this case, the travel speed was found to be approximately 950 km/s. This value matches well with the travel speed of the traveling disturbance observed by AIA as mentioned in the previous nugget. So perhaps, though other observatories (specifically coronagraphs) did not observe a CME, AIA did.

Figure 2: The radio spectrum from the Green Bank Solar Radio Burst Spectrometer (GBSRBS) shows a set of type III radio bursts and type II radio bursts. Type II radio bursts are signatures of traveling shock waves and are frequently associated with CMEs while Type III radio bursts are associated with escaping beams of accelerated electrons. The speed of propagation of this particular type II burst is around 950 km/s. Note the dark shadow of the SID (ionospheric absorption) below 10 MHz.

Flare morphology

To the solar west of the main flare site a significant elongated structure is present in multiple wavelengths, including 171A and 304 A, as shown in Figure 3. The presence of this structure is made more interesting by the fact that it reacts to the eruption of the main flare.

Figure 3: An elongated ribbon structure to the solar west of the flare site, visible in 171 A and 304 A.

Correlation maps

To study the morphology of this flare we introduce the method of cross-correlation mapping. This procedure is designed to uncover correlations between different portions of an image series.

The method is to select one pixel in the data cube to serve as the 'master pixel'. This pixel is represented by a time series. To create the correlation map, the master pixel is cross-correlated with every other pixel time series. Any pixel may be chosen to serve as the master pixel.

In this way we create two types of map. First, a map showing the level of correlation for a particular lag, and secondly a map showing the lag corresponding to the maximum correlation. We can use this method as a qualitative measure of the propagation of a disturbance along the structure.

We choose a master pixel located in the bottom-left corner of the ribbon structure. In multiple wavelengths, we can see the difference in the speed of propagation of heating along the structure as the energy from the main flare is deposited. In both 171 A and 304 A there is, on average, a considerable delay from the heating at the master pixel from the heating onset at the far end of the structure, a delay of over a minute for some pixels (see Figure 4). However, it appears that the propagation of this disturbance is slower in the 304 A channel than in 171 A. In principle we can use this method to measure the different propagation speeds of plasma at different temperatures and parts of the atmosphere.

Figure 4: Cross-correlation lag maps of AIA image cubes in the 171 A, 304 A and 1600 A bands.


Conclusion

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