Kp and Lattitude

[Guest Francis Audet]

Hi dear experts,

 

why is it that for example a Kp of 5 is required to potentially spark Auroras in the mid-west USA, at a lattitude of 46-47 Degrees, while that same Kp will only spark auroras at the 60 Degree in Europe? Has it to do (mainly, totally?) with the non-tru north magnetic north? Or is there something else at play here?

 

Thanks

 

 

[Vancanneyt Sander]

There is a difference in the geographic north and magnetic north:

 

Because the magnetic north is more south than the geographic north and that point is situated in favor of the US/Canada, Europe will get less aurorae on middle and lower geographic latitudes.

 

So in Geographic latitude speaking for Belgium: 52°N we need  a Kp-indice of 7 to view aurorae. In magnetic latitudes Belgium is at 45° magnetic latitude. If i look at the city Atlanta in the state Georgia USA it has a magnetic latitude if 44.5° so it's comparable. The geographic latitude is 33°N.

 

In our help article about the low, middle and high latitudes we have some images with the location of the oval for a given K-indice.

[Waldo Hazeleger]

A nice explanation is on this page.

Here you can see the difference between the magnetic latitudes of europe and north america, and what kp level is needed for auroral activity.