There is a magnetic bay in the X component indicative of substorm onset at 2246 at BJN, with a +Z/-Z variation indicating that the westward current intensifies first between BJN and TRO (where actually the eastward current grows at this time). The substorm jet than expands rapidly north (+Z), affecting but not reaching Hopen. This activity is very far north.
The electrojet intensifies again after 2300 and at 2315, when it finally reaches as far north as Hopen. Again +Z/-Z component transition is the main indicator. Y does not show much other than a southward component in the first activation, and a northward component in the current at the second one after 2300. This could imply that the first intensification was to the west of Scandinavia.
Before the main substorm, there was an eastward electrojet over the Arctic sae, starting to develop at about 13 UT (UT+2.5 hrs = MLT), slightly south or overhead of Hopen, moving south after 15 UT and passing BJN overhead at about 16 UT. It then lies between BJN and TRO for the rest of the evening. It intensifies a little with some auroral brightenings before 1800 and even later at 1930 and 2100 UT. No more, however, than a slight response to events far to the east. The substorm in this study (onset 2145) first results in an enhancement of the eastward electrojet between BJN and TRO, at 2230, the second enhancement something like a very far north reaching "Harang discontinuity" is carried into the sector, with East and westjet effects almost balancing to zero around BJN (it's a pity we have no more stations to cover these two jets and their separate effects), however, it is clear that Tromso sees some distant effect of it, negative X after 2200, and declining -Z after 2230. It is also clear that some E/W structure or gradient reached TRO at 2210 (neg Y spike). The arrival of the bright disturbance at our meridian is not until 2245, when BJN goes negative, Z changes from + to -, and TRO goes positive again. It is indicative of some kind of surge pattern, which is why it is thought that Scandinavia is initially west of the second auroral brightening, and was to far west of the first to see more that the effect on the driven eastward electrojet. The substorm electrojet expands north after the "WTS" reaches IMAGE, and intensifies a few more times.
More analysis needs to be done to find if there are any features associated with a transpolar arc - Polar coordinates are needed for this.