mirror of
https://github.com/JHUAPL/kaiju.git
synced 2026-01-08 22:58:05 -05:00
89 lines
3.1 KiB
ReStructuredText
89 lines
3.1 KiB
ReStructuredText
Non-Earth Planetary Magnetospheres
|
|
==================================
|
|
|
|
Instructions for running GAMERA-REMIX for non-Earth planetary magnetosphers.
|
|
|
|
By default, the voltron executable is designed to simulate Earth's
|
|
magnetosphere, and the config file assumes that the planet is Earth. This page
|
|
outlines how to run the model for non-Earth planetary magnetospheres, and what
|
|
assumptions are made in the model when doing so.
|
|
|
|
Model choices you should know about
|
|
-----------------------------------
|
|
|
|
Coordinate systems
|
|
^^^^^^^^^^^^^^^^^^
|
|
|
|
GAMERA and REMIX assume that the magnetic dipole axis is along the +z
|
|
direction. This means **the magnetic moment should always be positive**. The
|
|
sign of the corotation potential should be with respect to the orientation of
|
|
the rotation axis with the dipole axis. i.e., the corotation potential should
|
|
be positive if the two axes are aligned (e.g. Earth) and negative if they are
|
|
anti-aligned (e.g. Jupiter and Saturn). There is currently no correction to
|
|
the solar wind parameters with regard to the planet's coordinate system, so
|
|
you must do that conversion ahead of time.
|
|
|
|
IC files
|
|
--------
|
|
|
|
The default IC file, (src/voltron/ICs/earthcmi.F90), is specific to Earth's
|
|
magnetosphere. An alternative IC file, src/voltron/ICs/planetcmi.F90, can be
|
|
used as a more generic starting point. This may be used as-is for some simple
|
|
applications where only the planet parameters are changed.
|
|
|
|
You can configure voltron to build with this IC file either by setting the
|
|
``VOLTIC`` variable in ccmake, or by setting it as an argument with cmake:
|
|
|
|
``cmake <other_args> -DVOLTIC=$KAIJUHOME/src/voltron/ICs/planetcmi.F90 ..``
|
|
|
|
More specific configurations (e.g. Jupiter & Saturn with special initial
|
|
conditions, continuous mas loading from moons, etc.) should be defined in new
|
|
IC files using planetcmi.F90 as a starting point.
|
|
|
|
Config/XML file options
|
|
-----------------------
|
|
|
|
The planet parameters must also be specified in the xml config file. Here is
|
|
an example snippet:
|
|
|
|
.. code-block:: xml
|
|
|
|
<Kaiju>
|
|
<Gamera>
|
|
<prob planet="OTHER" x0="4913961" Rion="1.1" M0="0.1" Psi0="0"/>
|
|
</Gamera>
|
|
</Kaiju>
|
|
|
|
where
|
|
|
|
``Planet`` - Planet name. Mercury, Earth, Jupiter, and Saturn all have defined
|
|
parameters that don't need to be specified in the xml. "Other" can be used to
|
|
simulate a custom planet, where all parameters default to Earth unless
|
|
overwritten by any of the following:
|
|
|
|
``x0`` - Planet radius in meters
|
|
|
|
``Rion`` - Planetary ionosphere radius in planetary radii
|
|
|
|
``M0`` - Magnetic moment in Gauss (\ **Should always be positive.** See above
|
|
about coordinate systems)
|
|
|
|
``G0`` - Gravitational acceleration at planet surface in m/s^2 (e.g. 9.81 for
|
|
Earth)
|
|
|
|
``doGrav`` - uses ``G0`` to add gravitational term in GAMERA
|
|
|
|
``Psi0`` - Corotation potential in kV (See above about coordinate systems to
|
|
determine if it should be positive or negative)
|
|
|
|
``doCorot`` - uses ``Psi0`` to enforce corotation
|
|
|
|
It is also highly advised to tell REMIX to use a constant conductance, as the
|
|
more complex models are specific to Earth:
|
|
|
|
.. code-block:: xml
|
|
|
|
<REMIX>
|
|
<conductance const_sigma="T" ped0="1"/>
|
|
</REMIX>
|