magnetic_stripes.prm

# A model of a mid-ocean ridge that shows how magnetic lineations
# are created on the seafloor as the magnetic field changes its
# orientation over time.


set Additional shared libraries = ./libmagnetic_stripes.so

############### Global parameters

set Dimension                              = 2
set Start time                             = 0
set End time                               = 83.5e6
set Use years instead of seconds           = true
set Output directory                       = output-magnetic-stripes

subsection Discretization
  set Use discontinuous composition discretization = true

  subsection Stabilization parameters
    set Use limiter for discontinuous composition solution = true
    set Global composition maximum = 1
    set Global composition minimum = -1
  end
end

############### Parameters describing the model
# Let us here choose again a box domain (400 km wide and 100 km in depth)
# where we fix the temperature at the bottom and top,
# allow inflow from the bottom and outflow on the left and right,
# and prescribe the velocity along the top using the
# `function' description.

subsection Geometry model
  set Model name = box

  subsection Box
    set X extent = 400000
    set Y extent = 100000
    set X repetitions = 4
    set Box origin X coordinate = -200000
  end
end

subsection Boundary temperature model
  set Fixed temperature boundary indicators = bottom, top
  set List of model names = box

  subsection Box
    set Bottom temperature = 1600
    set Top temperature    = 293
  end
end

# The velocity along the top boundary models a spreading
# center of a mid-ocean ridge.
subsection Boundary velocity model
  set Prescribed velocity boundary indicators = left x:function, right x:function, top: function

  subsection Function
    set Variable names      = x,z
    set Function constants  = v=1, cm_per_year=0.02
    set Function expression = if(x>0, v * cm_per_year, -v * cm_per_year); 0
  end
end

subsection Boundary traction model
  set Prescribed traction boundary indicators = left y:initial lithostatic pressure, right y:initial lithostatic pressure

  subsection Initial lithostatic pressure
    set Representative point = 0,0
    set Number of integration points = 1000
  end
end

# We then choose a vertical gravity model and describe the
# initial temperature as a constant (being equivalent to a
# plate age of 0).
subsection Gravity model
  set Model name = vertical

  subsection Vertical
    set Magnitude = 10
  end
end

subsection Initial temperature model
  set Model name = function

  subsection Function
    set Variable names      = x,z
    set Function expression = 1600
  end
end

subsection Compositional fields
  set Number of fields = 1
end

subsection Initial composition model
  set Model name = function

  subsection Function
    set Variable names      = x,z
    set Function expression = 0
  end
end

subsection Boundary composition model
  set Fixed composition boundary indicators = bottom
  set List of model names = initial composition
end

subsection Material model
  set Model name = magnetic stripes

  subsection Composition reaction model
    set Thermal conductivity          = 4.7
    set Thermal expansion coefficient = 1e-4
    set Viscosity                     = 1e23
  end

  subsection Magnetic stripes model
    set Reversal times = \
8.350E+07, 8.272E+07, \
8.251E+07, 8.243E+07, \
8.173E+07, 8.155E+07, \
8.136E+07, 8.135E+07, \
8.092E+07, 8.046E+07, \
8.039E+07, 8.028E+07, \
8.017E+07, 7.992E+07, \
7.932E+07, 7.921E+07, \
7.902E+07, 7.888E+07, \
7.870E+07, 7.861E+07, \
7.852E+07, 7.827E+07, \
7.761E+07, 7.736E+07, \
7.723E+07, 7.693E+07, \
7.657E+07, 7.641E+07, \
7.637E+07, 7.633E+07, \
7.616E+07, 7.613E+07, \
7.607E+07, 7.594E+07, \
7.585E+07, 7.543E+07, \
7.528E+07, 7.524E+07, \
7.480E+07, 7.448E+07, \
7.427E+07, 7.419E+07, \
7.392E+07, 7.386E+07, \
7.376E+07, 7.362E+07, \
7.358E+07, 7.255E+07, \
7.245E+07, 7.240E+07, \
7.202E+07, 7.197E+07, \
7.157E+07, 7.142E+07, \
7.132E+07, 7.110E+07, \
7.082E+07, 7.079E+07, \
7.073E+07, 7.068E+07, \
7.051E+07, 7.036E+07, \
7.020E+07, 6.999E+07, \
6.980E+07, 6.942E+07, \
6.932E+07, 6.889E+07, \
6.870E+07, 6.861E+07, \
6.847E+07, 6.835E+07, \
6.749E+07, 6.721E+07, \
6.717E+07, 6.701E+07, \
6.694E+07, 6.677E+07, \
6.622E+07, 6.589E+07, \
6.522E+07, 6.472E+07, \
6.445E+07, 6.337E+07, \
6.298E+07, 6.278E+07, \
6.250E+07, 6.218E+07, \
6.173E+07, 6.164E+07, \
6.135E+07, 6.125E+07, \
6.104E+07, 6.101E+07, \
6.091E+07, 6.075E+07, \
6.070E+07, 6.043E+07, \
6.015E+07, 5.997E+07, \
5.982E+07, 5.970E+07, \
5.950E+07, 5.938E+07, \
5.877E+07, 5.872E+07, \
5.867E+07, 5.832E+07, \
5.800E+07, 5.785E+07, \
5.768E+07, 5.755E+07, \
5.751E+07, 5.695E+07, \
5.647E+07, 5.553E+07, \
5.522E+07, 5.499E+07, \
5.492E+07, 5.476E+07, \
5.410E+07, 5.384E+07, \
5.374E+07, 5.340E+07, \
5.302E+07, 5.256E+07, \
5.044E+07, 4.996E+07, \
4.885E+07, 4.856E+07, \
4.816E+07, 4.797E+07, \
4.782E+07, 4.716E+07, \
4.688E+07, 4.603E+07, \
4.590E+07, 4.565E+07, \
4.558E+07, 4.539E+07, \
4.507E+07, 4.395E+07, \
4.387E+07, 4.337E+07, \
4.224E+07, 4.198E+07, \
4.096E+07, 3.971E+07, \
3.724E+07, 3.559E+07, \
3.446E+07, 3.379E+07, \
3.272E+07, 3.255E+07, \
3.245E+07, 3.176E+07, \
3.114E+07, 3.084E+07, \
3.074E+07, 3.070E+07, \
3.060E+07, 3.015E+07, \
2.760E+07, 2.711E+07, \
2.595E+07, 2.559E+07, \
2.258E+07, 2.222E+07, \
2.100E+07, 1.987E+07, \
1.952E+07, 1.876E+07, \
1.792E+07, 1.589E+07, \
1.577E+07, 1.476E+07, \
1.243E+07, 1.216E+07, \
1.191E+07, 1.050E+07, \
1.021E+07, 1.013E+07, \
9.881E+06, 4.425E+06, \
5.000E+05
  end
end

# The final part of this input file describes how many times the
# mesh is refined and what to do with the solution once computed
subsection Mesh refinement
  set Initial adaptive refinement        = 4
  set Initial global refinement          = 3
  set Time steps between mesh refinement = 0
  set Strategy                           = minimum refinement function

  subsection Minimum refinement function
    set Variable names = depth, w
    set Function expression = if(depth<7000,7,if(depth<10000,6,if(depth<30000,5,if(depth<45000,4,3))))
  end
end

subsection Postprocess
  set List of postprocessors = visualization, temperature statistics, heat flux statistics

  subsection Visualization
    set Time between graphical output = 1e5
    set List of output variables = material properties, heat flux map, vertical heat flux

    subsection Material properties
      set List of material properties = density
    end
  end
end