Field line advection was one of the very unique features of Vapor 2, which was super useful for people working with data from solar MHD simulations. I am copying the following text from Vapor 2 documentation for context:
Field Line Advection
VAPOR GUI supports the ability to animate field lines or streamlines under the influence of a velocity field. The algorithm in VAPOR GUI was based on the work of Aake Nordlund, who proposed it as a means of animating magnetic field lines in a velocity field.
The user specifies a set of seed points for the steady (magnetic) field at a starting time T0.
These seed points are integrated in the steady field, resulting in a set of field lines.
Along each field line, the steady field magnitude is maximized, finding a point with the strongest steady field along that line.
The maximizing points are then advected in the unsteady (velocity) field to the next time step T1, to be used as seeds in the steady flow.
Steps 2 to 4 are repeated for each subsequent time step Tn.
For example, in my research work (Prasad et al. 2020), we used to put the three components of magnetic field Bx, By, and Bz as the steady-field and the three components of velocity, u, v and w as the unsteady field. Then field line advection would allow us to track the evolution of feature like a magnetic flux rope erupting during coronal mass ejection or solar flare.
So, I was wondering if a similar functionality can be supported in Vapor 3?
Reference: Prasad, A., Dissauer, K., Hu, Q., et al. 2020, ApJ, 903, 129
Thanks for posting this to the forum Avijeet. I’m going to open a ticket on our github repository that links to this. The team will assess it on Thursday but I’m 99% sure this won’t make it into the 3.7 release. I’m hoping that it makes it into 3.8 though.
I think that a big part of how the team decides what features to implement depends on how loud the demand is. I’m going to vouch for this feature, but if it gets remediated to a low priority then I may ask you to provide citations of where this feature has been published. I hope that’s not discouraging but our resources are limited - however Vapor’s user base needs to be heard and I’ll try to back you up on this. I think that citations on this feature will be the ultimate driver though.
I have also used field line advection in my analysis for solar flaring active region data. There used to be field line advection in VAPOR 2 but in VAPOR 3 it’s missing. I request to kindly add the field line advection in upcoming version. Following are the publications where VAPOR has been cited :
Field line advection is an important tool and helps to track the magnetic field lines effectively. I would definitely want to use this feature in my upcoming works. Therefore, I upvote the request to add field line advection in the latest version of VAPOR.
Yes, having field line advection back would be great! I use Vapor extensively in my work (citations pending on ongoing projects) and being able to do these calculations in Vapor would be tremendously helpful. The best alternative to something like field line advection is to use Lagrangian markers to trace the lines in the simulation itself (which we do) but not everyone has that option, especially as solar physics simulations can take months to run. Re-running with Lagrangian markers is expensive, and having field line advection as an option would save loads of time.
I completely agree with Avijeet that the field line advection is very crucial for the people studying MHD processes (such as magnetic reconnections, current sheets formations, MHD waves) numerically. In my recent work, I have exclusively used the field line advection for studying magnetic reconnection near the 3D null. Link of the paper is
I have used the field line advection scheme of old VAPOR and would like to use it further. It would be a great help to add it in newer versions of VAPOR.