SPICE Geometry calculator is your friend:
https://wgc.jpl.nasa.gov:8443/webgeocalc/46.9298 N, 75.3948 W
299,083 km
Sorry Mike, I had a lot of family in town for the holidays so I haven't been keeping up with Juno lately (besides I usually focus on JIRAM data when it hits the PDS). Congrats to your team on an amazing photo of a plume!
Now that I am back at work, I get a nice Io diversion! YAY!
Plume is from Chalybes Regio eruption, btw. Most significant post-NH eruption, has been ongoing since October 2008. I'm focusing mostly on the JIRAM image from the press release. I can say that the brightest hotspot is not Chalybes Regio, but Tvashtar, so that one is active again (it's been pretty quiescent for much of the Juno mission)