Changes between Version 11 and Version 12 of u/erica/MHDshocksReorientation

Timestamp:

03/09/16 16:14:31 (9 years ago)

Author:

Erica Kaminski

Comment:

—

u/erica/MHDshocksReorientation

@@ -16 +16 @@
 Now, the psuedo-colors plots are in the original coordinate system, whereas the vector plot has been tilted to look like the colliding flow scenario. The psuedo plots show that over the forward shock, the velocity field becomes completely parallel to the shock front (i.e. the x-component vanishes). This forces vy to go to zero over the slow shock front to maintain symmetry (the flow solutions must be rotationally-invariant). 
 
+Jonathan recently identified a way of decomposing the types of shocks in the simulations based on an eigen analysis. With this new code, we are able to see the different types of shocks present in the flow. For the MHD/infinite case, we see there are 5 wave fronts:
+
 Now, for the finite case, we have the following density plot:
 
@@ -23 +25 @@
 
 [[Image(vx_2dcf.png, 60%)]]
+
+and wavefront plot:
 
 When the scenario is finite, there is now pressure gradients between the collision refion and the ambient that allow for a radial expulsion of gas from the collision region. Over time in these plots, we see both the reorientation of the inner surface of the collision region, as well as the outer (fast) shock front. Here are 3 likely scenarios for the reorientation of the inner collision region. 
@@ -41 +45 @@
 In the hydro case, we do not see this reorientation (at least in 2D). Instead, we find a staircase effect. This seems to be getting generated by vortices above and below the collision region. Material that is deflected away from the flows by the shear, falls back down onto the cylinder due to pressure gradients. This additional material then creates more x-momentum/ram pressure, which drives the stair-casing structure.
 
+We can imagine writing these results up in a paper, which could have the following components:
 
-Another interesting feature present in the MHD case, is that the outer wave front (fast shock) stalls on the upper right/lower left of the collision interface. This is happening because there is a loss of magnetic pressure behind this wave front, and thus, the shock loses its support and stalls (see following figure of magnetic pressure map). The enhanced magnetic pressure, relatively speaking, in the contra regions are due to the combined effect of 1. the deflection of material and 2. the enhanced pressure from radial expansion. In regions where the magnetic pressure is strongest, the wave front is supported and continues to move outward, thus appearing to straighten the outer wave front.   
+1. Simulation results
 
-Now, Jonathan recently identified a way of decomposing the types of shocks in the simulations based on an eigen analysis. With this new code, we are able to see the different types of shocks present in the flow. For the MHD/infinite case, we see there are 5 wave fronts:
+2. Description of Jonathan's method for picking out types of shocks
 
-For the finite case now, here they are:
+3. Types of shocks present in the different cases
 
-We can imagine writing these results up in a paper, which could look like:
-
-Identify the wave structure, Jonathan's method for picking out types of shocks, and the shocks present in the different cases.
-
-Put problem in terms of beta and mach to allow for a predictive theory for reorientation.
+4. Predictive formula for reorientation in terms of beta and mach