10:26:20 From Steven Schwartz : The SNR data makes rather sweeping assumptions, uses some typical or average ISM parameters rather than point by point determinations 10:30:51 From Drew Turner : That’s kind of what I figured Steve… thanks! I’m really quite generally ignorant of the astrophysical analysis approaches though (but… I need to educate myself!) 10:32:37 From Lynn Wilson : They also assume isotropic Maxwellian (or Maxwell-Jüttner) VDFs with Te = Ti in the upstream (if they even assume an upstream plasma... some assume the shocks are propagating into a neutral fluid or even a vacuum in some models) 10:35:09 From Drew Turner : Oh the freedom of studying such poorly observable (i.e., constrained) systems…. ;P 10:35:48 From Drew Turner : (Poorly constrained == unconstrained) 10:38:03 From Lynn Wilson : Chat with an x-ray astronomer and ask them to show you one of their fits to the spectra that they use to invert the photon spectra to get electron spectra... I've seen them use upwards of ~8-10 different Maxwellians in the fit. 10:38:55 From Drew Turner : Yea, I know the challenges of such inversions very well from the BARREL balloon campaigns to study radiation belt precipitation into Earth’s atmosphere… 10:59:48 From Lynn Wilson : Do the amplitudes care about Mf? 11:06:35 From Shan Wang : @Ivan, What are the streaming ion populations responsible for the instability, upstream and downstream of the ramp? 11:24:13 From Drew Turner : dB becomes comparable to B0 and then start reconnecting 11:25:34 From Drew Turner : I assume they collapse faster because they are more likely to reconnect with the surrounding plasma, right? 11:27:00 From Imogen Gingell : Yes, I think so! 11:28:30 From Imogen Gingell : but I don’t think we can say for sure how much of the contract comes from reconnection emptying out the flux, and how much comes from contraction due to a lack of pressure balance across the structure - we do see that they aren’t in pressure balance, with bipolar force terms jxb-divP 11:28:43 From Imogen Gingell : I imagine its bit of both, but I don’t want to jump the gun! 11:29:28 From ljchen : Nice talk, Imogen - thank you! Is your hybrid simulation showing magnetic islands at the foreshock/shock 2D or 3D? What differences do you think2D and 3D simulations have in terms of island (flux rope) generations? 11:29:45 From Tomas Karlsson : could positiv and negative flux ropes be attracted to eachother because of oppositely directed diamagnetic currents? That could trigger reconnection quickly. 11:30:46 From ljchen : That’s an interesting point, Tomas! Coalescence. Marit has a paper reporting just that? 11:31:07 From Tomas Karlsson : Yeah, and mojtaba 11:31:51 From Imogen Gingell : I’s a 2D simulation. A 3D version is on my list of things to do. I expect that a 3D simulation would see a reduction in the reconnection rate 11:33:30 From Shan Wang : How to distinguish whether the rope-like structure has already reconnected to be a 'closed' rope or not? 11:38:58 From ljchen : Please keep us posted on your finding in 3D, Imogen. In 3D, the magnetic flux is not as confined as in 2D. It would be very interesting to see if there could be as many islands! 11:42:14 From Imogen Gingell : If we’re looking in 3D, I’m not sure that we can expect truly ‘closed’ flux ropes in the same way as you might see at the magnetopause. If the reconnection is patchy even at those waves, the ‘ends’ of the ropes are going to be open to the rest of the transition region. Another good reason to look at a 3D simulation!