Northern Lights

I only have limited experience (one trip) to Lapland. We flew via Finnair to Ivalo from HEL. Ivalo is the north most or nearly north most commercial airport in Finland. We bussed south to the Kiilopää Fell Center near the Urho Kekkonen National Park.

http://www.saariselka.fi/content/companies/suomen_latu_kiilopaa

Fell Centre Kiilopää is located in the southern part of the
Municipality of Inari, at the foot of the Kiilopää and Ahopää hills
and right by the Urho Kekkonen National Park. The 190-kilometre long
hiking and cross-country skiing trail network departs from the
courtyard. Part of the network also runs through the National Park.

http://en.wikipedia.org/wiki/Urho_Kekkonen_National_Park

https://www.youtube.com/watch?v=3aTnAJyt5qI
Aurora Borealis (1.5min) - Ivalo Finland Lapland, Kakslautanen Igloo Village.

Click below for previous posts that may be helpful:
https://community.ricksteves.com/travel-forum/general-europe/107927
https://community.ricksteves.com/travel-forum/general-europe/northern-lights-questions

Found this re Kiilopaa:
http://www.kiilopaa.fi/en/northern-lights.html

Don't know to what extent you can pick up and go, but here is a prediction site:
http://aurora.fmi.fi/public_service/
Click on "English" tab. You can subscribe to alerts.

Auroras Now! is a space weather service maintened by Finnish
Meteorological Institute (FMI) to help watching auroras in Finland.

The service includes auroral monitoring with the all-sky cameras and
magnetic field alarm systems for Northern and Southern Finland
separately . The magnetic alarms are base on the data of magnetometers
measuring the disturbance level of the Earth’s magnetic field at the
geophysical observatories in Nurmijärvi and Sodankylä.

PS. If you are combining Finland and Russia the Winter War history is an interesting background.