How precise is the Cactus Measurement?

[MinYoongi]

Today I've looked through the "New CME" tab that features Cactus Catalogue.

There was one CME in particular that cought my eye because there was such a big difference between the Minimum and the Maximum speed, the minimum being under 400 and Maximum almost at 1950. 

Can someone explain to me why the difference is that high? Is 1950km/s the true speed of the CME then? Would that qualify as a Carrington Event? (Thats a reach from my side 😅)

[Calder]

13 hours ago, MinYoongi said:

Today I've looked through the "New CME" tab that features Cactus Catalogue.

There was one CME in particular that cought my eye because there was such a big difference between the Minimum and the Maximum speed, the minimum being under 400 and Maximum almost at 1950. 

Can someone explain to me why the difference is that high? Is 1950km/s the true speed of the CME then? Would that qualify as a Carrington Event? (Thats a reach from my side 😅)

To my understanding, CMEs don’t travel the same velocity in all directions. So the min and max are just the lowest and highest velocities detected within the CME. Not sure how precise the Cactus measurements are. And no, the Carrington Event would’ve been faster and had other things contributing to its strength.

Also, in case I didn’t really answer your question… the forward motion (z) of the CME will, “from what I’ve seen”, be much faster than the lateral/vertical (x,y) motion. That probably makes up most of the difference, but when it comes down to internal parts, I don’t think we really understand the exact mechanism of how a CME launches the way it does. But I’d like to hear from others with more experience than me who might be able to explain further.

Edited April 29, 2022 by Calder

[Drax Spacex]

The last time I looked at this, in the case of an earthbound CME, what ended up being closest to the correct speed was something like the 75th percentile of all speed values on the scatter plot.

[lightpanther]

What's the story with an earthbound CME currently showing on the NASA-style simulation under the ENLIL menu item, but nothing on the NOAA simulation? And what CME is that anyway?