The 1859 Space Weather Event Revisited
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After more than 150 years, the space-weather event of 1859 associated | After more than 150 years, the space-weather event of 1859 associated | ||
- | with [ | + | with [http://adsabs.harvard.edu/abs/2012SoPh..280....1C Carrington's] name, continues to intrigue and inform us. |
- | It was | + | It was relatively well observed by the tools available |
at that early time, which of course did not include any of the electronics | at that early time, which of course did not include any of the electronics | ||
that we take for granted today. | that we take for granted today. | ||
- | The phenomena observed included the Carrington flare itself, plus | + | The phenomena observed included the Carrington white-light flare itself, plus |
- | + | prompt and delayed [https://en.wikipedia.org/wiki/History_of_geomagnetism geomagnetic] processes that (mostly in retrospect) laid the | |
- | foundation stones for [ | + | foundation stones for [http://spaceweather.com/ space weather] studies. |
- | + | ||
- | + | ||
- | + | ||
- | This "Carrington flare" is doubly | + | This "Carrington flare" is doubly distinguished both |
- | as the first reported solar flare and | + | as the first reported solar flare and and also because of its association with the largest |
geomagnetic disturbance yet recorded. | geomagnetic disturbance yet recorded. | ||
- | It | + | It remains the exemplar and guide for us as regards extreme space-weather |
events. | events. | ||
== Estimates of Event Magnitudes == | == Estimates of Event Magnitudes == | ||
- | In a recent paper [Ref. 1], | + | In a recent paper [Ref. 1], we have reassessed the size of the |
1859 event and its consequences. | 1859 event and its consequences. | ||
Our best guesses are as follows: a flare magnitude (soft X-ray classification) | Our best guesses are as follows: a flare magnitude (soft X-ray classification) | ||
- | and total (flare radiation plus CME kinetic) energy of | + | and total (flare radiation plus [https://en.wikipedia.org/wiki/Coronal_mass_ejection CME] kinetic) energy of |
- | ~X45 and ~ | + | ~X45 and ~2 x 10<sup>33</sup> erg, |
respectively (Figure 1); a >30 MeV proton fluence (F30) of | respectively (Figure 1); a >30 MeV proton fluence (F30) of | ||
- | ~10<sup>10</sup> cm<sup>-</sup> | + | ~10<sup>10</sup> pr cm<sup>-2</sup>; and a minimum Dst index of ~ -900 nT. |
These estimates and those measured for the closest modern competitors | These estimates and those measured for the closest modern competitors | ||
in each category are shown in tabular form here: | in each category are shown in tabular form here: | ||
- | Event GOES Energy | + | Event GOES Energy F30 Dst |
- | erg | + | (erg) (pr cm<sup>-2</sup>) (nT) |
SOL1859-09-01 X45 10<sup>32</sup> 1 x 10<sup>10</sup> -900 | SOL1859-09-01 X45 10<sup>32</sup> 1 x 10<sup>10</sup> -900 | ||
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SOL1921-05-14 -850 | SOL1921-05-14 -850 | ||
+ | The [http://www.ngdc.noaa.gov/stp/geomag/dst.html Dst] index is | ||
+ | one of the simplest and most important measures of global geomagnetic variability | ||
+ | during a [https://en.wikipedia.org/wiki/Geomagnetic_storm magnetic storm] | ||
+ | such as that associated with the 1859 event. | ||
The estimated geomagnetic Dst index for the Carrington magnetic storm, | The estimated geomagnetic Dst index for the Carrington magnetic storm, | ||
reduced from a reported -1760 nT value based on | reduced from a reported -1760 nT value based on | ||
- | Colaba (near Mumbai, India) observations, reflects direct | + | Colaba (near Mumbai, India) observations, reflects direct and indirect (Figure 2) evidence that the Colaba |
- | + | reading included an [auroral] component [Ref. 2]. | |
- | reading included an [auroral] component. | + | |
[[File:213f1.png|800px|thumb|center|Fig. 1: | [[File:213f1.png|800px|thumb|center|Fig. 1: | ||
Line 75: | Line 75: | ||
]] | ]] | ||
- | In a related paper | + | In a related paper [Ref. 3] we |
question the recent attribution of the cosmogenic nuclide event of | question the recent attribution of the cosmogenic nuclide event of | ||
- | 775 AD to the Sun | + | 775 AD to the Sun [Ref. 4]. |
- | Such a solar event would imply an F30 value of ~8 x 10<sup>10</sup> | + | Such a solar event would imply an F30 value of ~8 x 10<sup>10</sup> cm<sup>-2</sup> |
(approximately 10 times the value recorded during the three-month interval of | (approximately 10 times the value recorded during the three-month interval of | ||
sustained strong SEP activity from August-October 1989), a 1 GV proton fluence 45 | sustained strong SEP activity from August-October 1989), a 1 GV proton fluence 45 | ||
- | times larger than that of the February 1956 ground level event, | + | times larger than that of the February 1956 ground level event, and flare |
with a GOES classification of X230 (10<sup>34</sup> erg) flare. | with a GOES classification of X230 (10<sup>34</sup> erg) flare. | ||
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The solar flare and terrestrial effects of the Carrington space-weather | The solar flare and terrestrial effects of the Carrington space-weather | ||
event of 1859 are still of great current interest, and the work described | event of 1859 are still of great current interest, and the work described | ||
- | here is helping to place it in the context of recent | + | here is helping to place it in the context of recent observations. |
There is a caveat regarding the coincidence of first flare and | There is a caveat regarding the coincidence of first flare and | ||
greatest storm in the 1859 event. | greatest storm in the 1859 event. | ||
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reported was bound to have been a whopper. | reported was bound to have been a whopper. | ||
That said, there is no guarantee that a big flare will | That said, there is no guarantee that a big flare will | ||
- | produce a big magnetic storm, since | + | produce a big magnetic storm, since its heliographic position |
+ | and the orientation of the magnetic field in the accompanying CME are also crucially | ||
important for such effects. | important for such effects. | ||
The 4 August 1972 flare had a CME with a | The 4 August 1972 flare had a CME with a | ||
shorter transit time to Earth than that of the 1859 event (14.6 hr | shorter transit time to Earth than that of the 1859 event (14.6 hr | ||
vs. 17.5 hr) but the associated 1972 storm (Dst = -125 nT) does not | vs. 17.5 hr) but the associated 1972 storm (Dst = -125 nT) does not | ||
- | rank | + | rank near the top 25 of such events. |
== References == | == References == | ||
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[1] [http://adsabs.harvard.edu/abs/2013JSWSC...3A..31C "The 1859 space weather event revisited: limits of extreme activity"] | [1] [http://adsabs.harvard.edu/abs/2013JSWSC...3A..31C "The 1859 space weather event revisited: limits of extreme activity"] | ||
- | [2] " | + | [2] [http://adsabs.harvard.edu/abs/2006AdSpR..38..130G "Duration and extent of the great auroral storm of 1859"] |
- | [3] | + | [3] "On a solar origin for the cosmogenic nuclide event of 775 AD" |
[4] [http://adsabs.harvard.edu/abs/2013A%26A...552L...3U "The AD775 cosmic event revisited: the Sun is to blame"] | [4] [http://adsabs.harvard.edu/abs/2013A%26A...552L...3U "The AD775 cosmic event revisited: the Sun is to blame"] |
Revision as of 09:08, 24 November 2013
Nugget | |
---|---|
Number: | 213 |
1st Author: | Ed Cliver |
2nd Author: | |
Published: | November 25, 2013 |
Next Nugget: | TBD |
Previous Nugget: | Hard X-ray Footpoint Asymmetry |
List all |
Contents |
Introduction
After more than 150 years, the space-weather event of 1859 associated with Carrington's name, continues to intrigue and inform us. It was relatively well observed by the tools available at that early time, which of course did not include any of the electronics that we take for granted today. The phenomena observed included the Carrington white-light flare itself, plus prompt and delayed geomagnetic processes that (mostly in retrospect) laid the foundation stones for space weather studies.
This "Carrington flare" is doubly distinguished both as the first reported solar flare and and also because of its association with the largest geomagnetic disturbance yet recorded. It remains the exemplar and guide for us as regards extreme space-weather events.
Estimates of Event Magnitudes
In a recent paper [Ref. 1], we have reassessed the size of the 1859 event and its consequences. Our best guesses are as follows: a flare magnitude (soft X-ray classification) and total (flare radiation plus CME kinetic) energy of ~X45 and ~2 x 1033 erg, respectively (Figure 1); a >30 MeV proton fluence (F30) of ~1010 pr cm-2; and a minimum Dst index of ~ -900 nT. These estimates and those measured for the closest modern competitors in each category are shown in tabular form here:
Event GOES Energy F30 Dst (erg) (pr cm-2) (nT) SOL1859-09-01 X45 1032 1 x 1010 -900 SOL2003-11-04 X35 1033 SOL1972-08-04 5 x 109 SOL1921-05-14 -850
The Dst index is one of the simplest and most important measures of global geomagnetic variability during a magnetic storm such as that associated with the 1859 event. The estimated geomagnetic Dst index for the Carrington magnetic storm, reduced from a reported -1760 nT value based on Colaba (near Mumbai, India) observations, reflects direct and indirect (Figure 2) evidence that the Colaba reading included an [auroral] component [Ref. 2].
In a related paper [Ref. 3] we question the recent attribution of the cosmogenic nuclide event of 775 AD to the Sun [Ref. 4]. Such a solar event would imply an F30 value of ~8 x 1010 cm-2 (approximately 10 times the value recorded during the three-month interval of sustained strong SEP activity from August-October 1989), a 1 GV proton fluence 45 times larger than that of the February 1956 ground level event, and flare with a GOES classification of X230 (1034 erg) flare.
Conclusion
The solar flare and terrestrial effects of the Carrington space-weather event of 1859 are still of great current interest, and the work described here is helping to place it in the context of recent observations. There is a caveat regarding the coincidence of first flare and greatest storm in the 1859 event. Hugh Hudson (personal communication, 2013) cautions that the first flare reported was bound to have been a whopper. That said, there is no guarantee that a big flare will produce a big magnetic storm, since its heliographic position and the orientation of the magnetic field in the accompanying CME are also crucially important for such effects. The 4 August 1972 flare had a CME with a shorter transit time to Earth than that of the 1859 event (14.6 hr vs. 17.5 hr) but the associated 1972 storm (Dst = -125 nT) does not rank near the top 25 of such events.
References
[1] "The 1859 space weather event revisited: limits of extreme activity"
[2] "Duration and extent of the great auroral storm of 1859"
[3] "On a solar origin for the cosmogenic nuclide event of 775 AD"
[4] "The AD775 cosmic event revisited: the Sun is to blame"
RHESSI Nugget Date | 25 November 2013 + |
RHESSI Nugget First Author | Ed Cliver + |
RHESSI Nugget Index | 213 + |