2D Simulations

Summary

Summary

List of simulations

\beta	Ma	Thickness (\text{cm}^2)	MinDensity (\text{cu}) or (\text{dynes}/\text{cm}^2)	Completed as of 04-20
10	20	0.01	1d-10	Frame 184
		0.03	0.01, after frame 90	Frame 101
		0.06	0.01, after frame 110	Frame 110
	3	0.01	0.01	X
		0.03	0.01	X
		0.06	0.01	X
0.1	20	0.01	1d-10	Yes
		0.03	0.01, after frame 45	Frame 58
Hydro	20	0.01	1d-10	Yes
		0.03	1d-10	Yes
		0.06	1d-10	Yes
Total No.	11

Parameters in .data files

• In physics.data the MinDensity has been changed for some of the slower runs. I have denoted above where I change the minimum density during the time of the simulation.
• Three of the simulations are hydro, so we simply turn off the MHD in physics.data.
• Three of the simulations have a Mach No. = 3. So we multiply the final_time = .02d0 of the Mach No. = 20 simulations by the ratio of the mach numbers, (20/3), to get a new final_time = 1.33d0 for these Mach No. = 3 simulations.

Here is the problem.data for these simulations:

&ProblemData
spacing=.2           ! Lattice constant
thickness=0.01        ! Radius of wire: 0.01, 0.03, 0.06
beta=10             ! magnetic beta: 0.1, 10
mach=20              ! mach number: 3, 20
screen_x=.25         ! location of screen in x
rho_wire=1000d0       ! peak density of screen
rho_wind=1d0     ! density of wind
rho_amb=.01          ! ambient density
/

Note that the values of thickness, beta, and mach, are listed in the comment.

Here is a copy of the space parameters in the global.data:

&GlobalData

!=============================================================================================
! Parameters Related to Space
!=============================================================================================
nDim     = 2                            ! number of dimensions for this problem (1-3)
GmX      = 3200,160,160                 ! Base grid resolution [x,y,z]
MaxLevel = 1                            ! Maximum level for this simulation (0 is fixed grid)
LastStaticLevel = -1                    ! Use static AMR for levels through LastStaticLevel [-1]
GxBounds = 0d0,0d0,0d0,4d0,.2d0,.2d0    ! Problem boundaries in computational units,format:
                                        ! (xlower, ylower, zlower, xupper, yupper, zupper)
                                        ! For 2D problems, set zlower and zupper to 0.d0.

Gmthbc   = 1,2,2,1,2,2                  ! Sets the physical boundary conditions at the edge of the problem domain
                                        ! format:  (x1, y1, z1, x2, y2, z2)
                                        ! 1-Extrapolated,
                                        ! 2-Periodic,
                                        ! 3-ReflectingWall (Field lines do not penetrate)
                                        ! 4-Reflect_BParallel (Field lines held normal
                                        ! 5-Reflect_Cylindrical (Like reflect wall, but also changes sign of phi
                                        !                        components of velocity and magnetic fields)
                                        ! [1,1,1,1,1,1]

In summary we have 11 2D simulations with 1 level of AMR with periodic boundary conditions. Thus we can visualize the simulations used the replicate operator in Visit. We expect the simulation box to be very long and thin given the GxBounds. There is a high level for the base grid resolution — given approximately half a million cells in the base grid. So these jobs, despite being 2D, are high resolution.

Visualizations (Table)

Visualizations (Table)

Beta	Picture at Final Frame (200)	GIF	Notes & Questions
0.1 (Strongest Magnetic Pressure)		​GIF	- Strongest magnetic pressure (\beta = 0.1), wire radius, i.e. thickness = 0.01, Ma = 20 - "Clumps" seem to grow in density over the evolution of the simulation. Starting with a wire radius of 0.01, it clearly grows to a larger radius (~0.03 cm). This seems to start once the clump moves past x = 0.6 cm. - The clumps get pushed back incredibly far. Starting at x_{i} = 0.25 \text{cm}, ending at x_{f} = 2.75 \text{cm}. Perhaps this is due to the high magnetic pressure. - A low density (0.5 \text{dynes}/\text{cm}^2) region forms behind the clump at around x = 0.7 cm. - Unclear when the clump stops accreting.
Hydro (MHD Off)		​GIF	- Hydro (MHD off), thickness = 0.01, Ma = 20
		​GIF	- Hydro (MHD off), thickness = 0.03, Ma = 20
		​GIF	- Hydro (MHD off), thickness = 0.06, Ma = 20