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CME approach

Guest Stephane Mabille

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Directed mostly away from our planet? Faint impact on our geomagnetic fields... had ringing in the ears the last few days up here in northern Canada and U.S... commented by some folks, possibly from geomagnetics going on. Anybody else ? Keep well everyone!☼

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There is no evidence that space weather can cause ringing ears or any other medical conditions to people here on Earth.

It was obvious that this CME was mostly directed SE and away from our planet but a glancing blow couldn't be excluded. It seems now that it was a miss or it was so weak that it was somehow embedded in the coronal hole stream. My money is on that it was a miss.

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Someone had an interesting theory that the CMS from the M3.9 event on 09/13:12 did not missed us.

There were two glitches detected on ACE Swepam which you would normally describe as just that: A glitch. But these ones happened with the timing correct for a CME travelling at 950 km/s

The facts:
- The M3.7 event occured at 09/13:12
- It was accompanies with a Type-II radio sweep at 952 km/s
- A glitch in Ace Density of 30.1 was detected at 10/08:55
- A glitch in Ace Speed of 946.7 was detected at 10/15:21 (26 hours after the M3.7 event)
- An swpc alert ALTK05 occured at 10/13:09
- An swpc alert ALTK06 occured at 10/14:30

See also the pictures from ace and kiruna. What are your thoughts?





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I know where you got this theory from and no the Sun doesn't cause earthquakes.

Anyway, why would just 1 data point (which is just one minute) show such an extraordinary high solar wind speed (or density a little earlier) reading and other data points surrounding it show much lower values. A CME doesn't pass Earth in one minute. Shouldn't there be higher values that last for multiple hours instead of a single minute? And why was there no increase in the IMF Bt which is a classic CME sign? SWEPAM glitch is suspect number one. ACE is getting old. Glitches happen.

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Yes, you are right about the source of this theory (Mr. Ben).

I did some calculations myself, and he made a mistake anyway in the travel time for the solar wind (or CME) from sun to earth. He indicated that 900 km/s would take 28 hrs and 1000km/s takes 26 hrs.

The right calculation is as follows: 
- Distance sun - earth: 150.000.000 km
- Speed 950 km/s makes 157894 seconds
- 3600 seconds in an hour makes 43.85 hrs, (not 26 hrs).

By the way: The glitch took a little bit more than just one minute.

Ace Density:
10/08:54    2.0
10/08:55    30.1
10/08:56    16.1
10/08:57    2.5

Ace Speed:
10/15:19    676.3
10/15:20    946.7
10/15:21    867.4
10/15:22    716.2

I agree with you that a CME takes much longer than one minute to get passed earth. My guess was that the Coronal Hole high speed stream that we were already in when the CME happened caused much faster travel speed for the CME than normal and that it "consumed" most of the CME particles.


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To all glitch 'believers'. If you would look a bit deeper into the data you would have seen that those data points of the density part where false data records. Status code for those data points was NOT nominal data! NOAA indicated those data points as bad data record.

And to the difference in speed. The speed is determined by taking the average speed of the particles in the solar wind. When the density is very low and there are only a few particles per cc, an inaccurate speed reading is always possible. Resulting in sometimes 'abnormal' spikes. When density is low, the solar wind speed can have those so called weird heights and lows but are just normal. 

Case closed.

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Well, excuse me for (trying) to find an explanation for the CME miss. A huge mistake from me that I did not realize that a glitch of a few minutes cannot be a CME pass.

Now I look further into the data, the 30.1 indeed was indicated as a false record, but the 16.1 was not. And the speed data was also not indicated as false data, but you explained why that can happen.

Conclusion is clear: The CME was indeed a miss, and the glitch is just a glitch.


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