A few days overdue on this one....
Late on the 13th and through the early hours of the 14th Earth's magnetic field felt a blow of plasma waves from a weak and slow moving CME that erupted from the Sun a five days earlier. These caused the usual response on my magnetometer buried in my back garden, as shown below. Usually I record data at a cadence of 150 seconds, but more recently with a new PC I've been recording additionally at a cadence of 1 second for higher resolution. This has paid off since I've been able to resolve what I think might be PC3-4 waves (or ripples since they are superimposed onto the main longer frequency waves). Some background information can be found here: https://agupubs.onlinelibrary.wiley.com ... 17JA025033
These have been known about for over 50 years, so nothing new, but this is the first time I've recognised such 'ripples' in my data. I don't know what they are for certain, but there is definitely some structure there.
Here's the main event:
and the finer details in high resolution 1s cadence recordings (timestamp as shown)...
The Sun might be quiet at the moment, but there are still lots of interesting phenomenon to study.
Thanks for looking.
Stu.
Weak CME impact 13th July 2020
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Weak CME impact 13th July 2020
H-alpha, WL and Ca II K imaging kit for various image scales.
Fluxgate Magnetometers (1s and 150s Cadence).
Radio meteor detector.
More images at http://www.flickr.com/photos/solarcarbon60/
Fluxgate Magnetometers (1s and 150s Cadence).
Radio meteor detector.
More images at http://www.flickr.com/photos/solarcarbon60/
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Re: Weak CME impact 13th July 2020
Very interesting data Stuart, you will soon be recognized as a professional station
Alexandra
Alexandra
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Re: Weak CME impact 13th July 2020
Stu: You’ve definitely uncovered more interesting behaviour with your high cadence upgrade.
If you would like, send me an ASCII data file of of this run. I could try to do a Fourier analysis and see what the ripple “frequency spectrum” looks like. Seems to be a pretty well-defined frequency.
Cheers.
Peter
If you would like, send me an ASCII data file of of this run. I could try to do a Fourier analysis and see what the ripple “frequency spectrum” looks like. Seems to be a pretty well-defined frequency.
Cheers.
Peter
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Re: Weak CME impact 13th July 2020
Many thanks Alexandra/Peter.
Peter, I can send a CSV file with time stamps and sensor frequency if you can work with that, or an excel file if you prefer.
Thanks for taking the time to take a look at the data.
Stu
Peter, I can send a CSV file with time stamps and sensor frequency if you can work with that, or an excel file if you prefer.
Thanks for taking the time to take a look at the data.
Stu
H-alpha, WL and Ca II K imaging kit for various image scales.
Fluxgate Magnetometers (1s and 150s Cadence).
Radio meteor detector.
More images at http://www.flickr.com/photos/solarcarbon60/
Fluxgate Magnetometers (1s and 150s Cadence).
Radio meteor detector.
More images at http://www.flickr.com/photos/solarcarbon60/
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Re: Weak CME impact 13th July 2020
Fascinating stuff Stu! It's shame your data isn't streamed live, it would be really interesting to see how the graph responds to real time aurora when in Iceland.
http://brierleyhillsolar.blogspot.co.uk/
Solar images, a collection of all the most up to date live solar data on the web, imaging & processing tutorials - please take a look!
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Re: Weak CME impact 13th July 2020
Thanks Mark.
I'll have to look into how to do that, Mark. It would have to be the raw version as captured.
Thanks also Alexandra/Peter.
Stu.
I'll have to look into how to do that, Mark. It would have to be the raw version as captured.
Thanks also Alexandra/Peter.
Stu.
H-alpha, WL and Ca II K imaging kit for various image scales.
Fluxgate Magnetometers (1s and 150s Cadence).
Radio meteor detector.
More images at http://www.flickr.com/photos/solarcarbon60/
Fluxgate Magnetometers (1s and 150s Cadence).
Radio meteor detector.
More images at http://www.flickr.com/photos/solarcarbon60/
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Re: Weak CME impact 13th July 2020
Hi Stu.
The attached image summarizes my attempt at Fourier analyzing the magnetometer data.
Panel (a) shows the raw magnetometer data that you sent me along with a smoothed version (7000 point Savitzky-Golay). The horizontal scale is measured in seconds with t=0 corresponding to date/time 2020-07-13 00:00:00. In panel (b), I used the smoothed data as a rough "baseline" to get rid of the overall slow time variation by subtracting this baseline from the raw data. The result of a fast fourier transform (fft) applied to the entire dataset shown in (b) is given in panel (c). It's pretty choppy! On a smaller horizontal scale, I discerned the rough indications of a peak so I applied some smoothing (100 points SG) to the fft and plot this together with the unsmoothed fft spectrum (plotted as scattered points) in panel (d). The smoothed curve shows some pretty good evidence of peaks at 2.6 mHz and 4.8 mHz (marked by the arrows in the figure). These oscillation frequencies are definitely within the range (1.7–6.7 mHz) expected for Pc5 waves, as quoted in the article you've referenced. It looks like you've observed two rather well defined resonances. There's not much evidence for anything happening at higher frequencies. I haven't read enough to grasp the physics of all this but it definitely makes for an interesting observation!
All the best.
Peter
The attached image summarizes my attempt at Fourier analyzing the magnetometer data.
Panel (a) shows the raw magnetometer data that you sent me along with a smoothed version (7000 point Savitzky-Golay). The horizontal scale is measured in seconds with t=0 corresponding to date/time 2020-07-13 00:00:00. In panel (b), I used the smoothed data as a rough "baseline" to get rid of the overall slow time variation by subtracting this baseline from the raw data. The result of a fast fourier transform (fft) applied to the entire dataset shown in (b) is given in panel (c). It's pretty choppy! On a smaller horizontal scale, I discerned the rough indications of a peak so I applied some smoothing (100 points SG) to the fft and plot this together with the unsmoothed fft spectrum (plotted as scattered points) in panel (d). The smoothed curve shows some pretty good evidence of peaks at 2.6 mHz and 4.8 mHz (marked by the arrows in the figure). These oscillation frequencies are definitely within the range (1.7–6.7 mHz) expected for Pc5 waves, as quoted in the article you've referenced. It looks like you've observed two rather well defined resonances. There's not much evidence for anything happening at higher frequencies. I haven't read enough to grasp the physics of all this but it definitely makes for an interesting observation!
All the best.
Peter
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Re: Weak CME impact 13th July 2020
Loving the science here guys!
http://brierleyhillsolar.blogspot.co.uk/
Solar images, a collection of all the most up to date live solar data on the web, imaging & processing tutorials - please take a look!
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Re: Weak CME impact 13th July 2020
Many thanks, Peter, for taking the time and trouble to undertake the analysis.
Good to see your results confirming the effect is real and not just my wishful thinking.
Stu.
Good to see your results confirming the effect is real and not just my wishful thinking.
Stu.
H-alpha, WL and Ca II K imaging kit for various image scales.
Fluxgate Magnetometers (1s and 150s Cadence).
Radio meteor detector.
More images at http://www.flickr.com/photos/solarcarbon60/
Fluxgate Magnetometers (1s and 150s Cadence).
Radio meteor detector.
More images at http://www.flickr.com/photos/solarcarbon60/