Changes between Version 24 and Version 25 of PhysicsDataExplained


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Timestamp:
06/11/11 23:41:26 (14 years ago)
Author:
Brandon Shroyer
Comment:

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  • PhysicsDataExplained

    v24 v25  
    6565 * '''''{{{pScale:}}}'''''   The pressure scale [dynes/cm^2^].  {{{pScale}}} is only used if {{{TempScale}}} is set to 0.0; otherwise it is derived from {{{pScale}}}.  Again, {{{TempScale}}} and {{{pScale}}} should not both be 0.
    6666
    67  * '''''{{{lScale:}}}'''''   The length scale in [cm].  This defines 1 ''computational unit'' (the units used in [GlobalDataExplained global.data] to define the size of the domain).
     67 * '''''{{{lScale:}}}'''''   The length scale in [cm].  This defines 1 ''computational unit'' (the units used in [GlobalDataExplained#GlobalData global.data] to define the size of the domain).
    6868
    6969[[BR]]
    7070
    71 === Source Term Switches & Parameters ===
     71=== MHD Variables ===
    7272
    73  * '''''{{{iCylindrical:}}}'''''  Specifies whether there is cylindrical symmetry in the problem. 0 - no, 1 - yes, 2 - 2D cylindrical with v_phi (hydro only).
    74  * '''''{{{iSymAxis:}}}'''''  Specifies the location of the symmetry axis if iCylindrical is set to 1 or 2;  0 - along the x-axis, 1 - along the y-axis.
    75  * '''''{{{lPrimitive:}}}''''' Logical.  Currently can be omitted (and is not actually in physics.data as of r445 ), but default value is set = .TRUE. in revision r445, so if you want to work with conservative variables, add lPrimitive here and set to {{{F}}}.  See [wiki:ProgramUpdate20090615 here] for more information.
    76 
    77  * '''''{{{iCooling:}}}'''''  Specifies whether radiative cooling is occurring.
    78   * 0 - No cooling
    79   * 1 - Simple Dalgarno-!McCray cooling.  The file TABLES/cooling.tab must be present.
    80   * 2 - Cooling with microphysics.  The file neqcool.dat, plus the tables TABLES/DMcooling.tab, TABLES/Hexcooling.tab must be present.
    81   * 3 - Analytic cooling.  Used for for some testing purposes (?)
    82   * 4 - Inoue & Inutsuka cooling function.  The file TABLES/IIcooling.tab must be present.
    83  * '''''{{{MinTemp:}}}'''''  The minimum allowed temperature for the cooling regime, if iCooling is 1.
    84 
    85  * '''''{{{iRadForce:}}}'''''  Specifies a central radiative driving force in the system. 0 - no, 1 - yes.  SOURCE ASSUMED TO BE IN THE LOWER LEFT CORNER.  ONLY 2D!
    86  * '''''{{{Lumin:}}}'''''   The effective luminosity of the central source for radiation driving, normalized to Eddington luminosity.  Only used if iRadForce = 1.
    87 
    88  * '''''{{{iGravity:}}}'''''  Specifies a central gravitational force in the system.
    89   * 0 - No gravity
    90   * 1 - Gravitational source assumed to be in the left lower corner.  Only 2D.  [wiki:Gravity Click here for subroutine]
    91   * 2 - Uniform gravity applied along lower boundary.  [wiki:UniformGravity Click here for subroutine]
    92   * 3 - Self-gravity, with or without sink particles (depending on iSink flag).
    93  * '''''{{{mCentral:}}}'''''   The mass of the central gravitating body [Solar Masses].  Only used if iGravity = 1.  Actually used in iGravity = 2 as well, but not as solar masses (input mCentral as acceleration in cgs instead... this may be changed in upcoming revisions).
    94 
    95  * '''''{{{SrcPrecision:}}}'''''  Precision of the source term integration on every level including level -1.  Note: There must be as many values specified for this array as there are AMR levels + 1.
    96 
    97 [[BR]]
    98 
    99 
    100 === Type of Riemann solver to be used on each refinement level ===
    101 
    102  * '''''{{{RSType:}}}'''''   The type of Riemann solver to be used on each AMR level.  0 - approximate Roe Solver, 1 - exact Riemann Solver.  There must be as many values specified for this array as there are AMR levels + 1.
    103 
    104  * '''''{{{ViscCD:}}}'''''   This term allows for artificial viscosity in the contact discontinuity between grids to prevent carbuncles.  0 - off, 1 - on, 2 - ?.  Can only be run with the exact Riemann Solver.
    105 
    106  * '''''{{{ViscLOF:}}}'''''   Deprecated variable.  If used, this term must be set to a real value.  Can be commented out in most cases.
    107 
    108  * '''''{{{iEOS:}}}'''''   The equation of state type used for the exact solver.
    109   * 0 - ideal gas
    110   * 1 - different isentropic gamma and ratio of specific heats
    111   * 2 - analytic Thomas Fermi EOS.
    112   * 3 - vanderWaals
    113   * 4 - isothermal
    114 
    115 
    116  * '''''{{{PMinRealGas:}}}'''''   The minimum pressure allowed in the Thomas Fermi EOS, dyne/cm^2^.  Only used if iEOS = 2.
    117 
    118 [[BR]]
    119 
    120 === Verbosity of the output of various runtime diagnostic messages to "xbear.log" ===
    121 
    122 
    123  * '''''{{{Verbosity:}}}'''''   This array contains three values to control the error messages that appear. 
    124 The first value sets the cell protection error messages (0 - none, 1 - all messages).[[BR]] 
    125 The second value sets the source term messages (0 - none, 1 - minimal, 2 - all messages).[[BR]] 
    126 The third value sets the exact Riemann solver messages (0 - none, 1 - minimal, 2 - all messages).[[BR]]
    127 
    128 [[BR]]
    129 
    130 === Protection routine switches ===
    131 
    132  * '''''{{{iProtect:}}}'''''   This switch sets the type of protection method used to protect against negative and small values of pressure and density.
    133   * 0 - no protection[[BR]]
    134   * 1 - resets protected cells to the values of the neighbor cell with the minimum value of Presure/density [[BR]]
    135   * 2 - resets protected cells to the values of the neighbor cell with the minimum value of Pressure [[BR]]
    136   * 3, 4 are nominally the same options as 1 and 2, but also include entropy conservation.  These options are deprecated in the current version of the code, and should not be used.  See [wiki:Protect] for more information.
    137   * 5 - average neighbor Pressure and density [[BR]]
    138 
    139 [[BR]]
    140 
    141 === MHD related section ===
    142 
    143  * '''''{{{iDivB:}}}'''''   Numerical method of preventing magnetic field divergence.  See ConstrainedTransport for more information.
    144   * 1 - Ryu Jones CT
    145   * 2 - Dia Woodward CT
    146   * 3 - Balsara Spicer CT
    147   * 6 - Gardiner and Stone but only works for method(1)=1
    148 
    149  * '''''{{{lMHD:}}}'''''   Logical switch to say whether there is MHD in the problem.  T/F value only.
    150 
    151  * '''''{{{Bbeta:}}}'''''   The plasma parameter beta, or the ratio of thermal energy density to magnetic energy density.  Also the ratio of plasma pressure to the magnetic pressure
    152 
    153  * '''''{{{MACH:}}}'''''   A Mach number setting, if needed in a particular problem setup.
    154 
    155  * '''''{{{TEST_MHD:}}}'''''   This is set = 1 in the current physics.data.  I'm not sure what it does.
     73 * '''''{{{lMHD:}}}'''''   Logical switch used to turn MHD on or off.  MHD requires the face-centered {{{aux}}} array, so if you turn MHD on, be sure to set {{{MaintainAuxArrays}}} in [GlobalDataExplained#GlobalData global.data] to {{{T}}}.
    15674
    15775[[BR]]
     
    15977=== Tracer Settings ===
    16078
    161  * '''''{{{iLTracer:}}}'''''   A switch to set the type of tracer fields.  If iLTracer is set greater than or equal to 1, tracers will be turned on.  If iLTracer is on it works on all variables between nTracerLO and nTracerHI. See [wiki:VanLeer] for more information.
    162   * 0 = Conservative Tracer constrained between 0 and the density.  Must choose this for Species tracking (which uses the tracer fields), or for no tracers.
    163   * 1 = Lagrangian Tracer constrained between 0 and 1
    164   * 2 = Lagrangian Tracer constrained to be 0 or greater
    165  * Warning: This applies for all tracers.
     79Tracer variables are used to track the movement of specific quantities of matter within your simulation.  If, for instance, you had one or more clumps suspended in an ambient medium and wanted to track the way the clump matter moves through the domain, you would use a tracer.
    16680
     81 * '''''{{{iLTracer:}}}'''''   Controls the behavior of tracer fields.
     82  * {{{0 -- Conservative:}}} Tracer values in a given cell are constrained from 0 to {{{density}}}.  If you do not intend to use tracers, then select this option.
     83  * {{{1 -- Limited Lagrangian:}}}  Tracer values are constrained between 0 and 1
     84 These settings apply to ''all'' tracer fields--AstroBEAR does not allow users to mix conservative and Lagrangian tracers in one problem.
     85
     86 * ''''''{{{NrTracerVars:}}}'''''  Indicates the number of tracer variables to use in this problem.  If {{{NrTracerVars}}} is {{{0}}}, then tracers will not be active.  Tracking tracer variables costs memory and CPU cycles, so it's best to leave this switched off if you don't anticipate needing them.  Under no circumstances should {{{NrTracerVars}}} be less than 0.
    16787[[BR]]
    168 
    169 === (Cosmic Ray) CR related section ===
    170 In order to run CR portion of code, MHD must be on and iLTracer must be 2. See [wiki:CosmicRay] for more information.
    171 
    172  * '''''{{{lCR:}}}'''''  Turns Cosmic Rays on and off.
    173 
    174  * '''''{{{lCRfeed:}}}'''''   Turns Cosmic Ray feedback on and off.  Cosmic Rays provide an extra pressure to the fluid flow.  By turning this on you turn on the CR pressure term which will add into the dynamics of the flow.
    175 
    176  * '''''{{{iAtrans:}}}'''''   Turns on and off Alfven Transport where 1 is on and 0 is off. Alfven Transport deals with the heating from Alfven wave production at shocks by Cosmic Ray streaming.  This changes both the scattering center velocities for the CRs and the gas pressure by adding an addition pressure due to Alfven wave dissipation.
    177 
    178  * '''''{{{lCREl:}}}'''''   Turns on and off the CR electron energy losses due to synchrotron and inverse Compton radiation.
    179 
    180  * '''''{{{nj:}}}'''''   Number of Species.  If 1 and Energy Losses are active then it is electrons, otherwise 1 is proton and 2 is electron.  Currently only 2 species are allowed.
    181 
    182  * '''''{{{nplow:}}}'''''   Info%q variable index for start of CR variables; should be 1 higher than any tracers.  More details on the storage of CRs is located in [wiki:CosmicRay].
    183 
    184  * '''''{{{np:}}}'''''     Number of Momentum Bins.
    185 
    186  * '''''{{{ylow:}}}'''''   ln(plow), the log of the minimum momentum (i.e. the momentum value for the lowest momentum bin) in code units (in units of m_p*c, where m_p is the mass of the proton and c is the speed of light).
    187 
    188  * '''''{{{yhigh:}}}'''''  ln(phigh), the log of the maximum momentum in code units
    189 
    190  * '''''{{{dlp0:}}}'''''   ln(dp), the log of the momentum bin size.  Note this is currently set to be constant.
    191 
    192  * '''''{{{ceps1:}}}'''''  Injection fraction for species 1.  Basically at a shock this determines the fraction of material passing through the shock that becomes CRs.
    193 
    194  * '''''{{{ceps2:}}}'''''  Injection fraction for species 2.
    195 
    196  * '''''{{{ckapp:}}}'''''  Diffusion scaling for the parallel (parallel to the shock normal) diffusion coefficient.
    197 
    198  * '''''{{{rkap:}}}'''''   kper/kpar, The ratio of the perpendicular diffusion to the parallel diffusion
    199 
    200  * '''''{{{alph:}}}'''''   The momentum powerlaw dependance of the diffusion, 1=Bohm diffusion.  More details on the diffusion coefficient is located in [wiki:CosmicRay].
    201 
    202  * '''''{{{beta0:}}}'''''  1/c, where c is the speed of light, in code units.  This is needed to set the CR pressure and other things in the CR routine.
    203 
    204  * '''''{{{ucmb:}}}'''''   The CMB/Radiation energy density in code units.  The energy density has the same units as the magnetic energy density.
    205 
    206  * '''''{{{tsc:}}}'''''    The synchrotron lifetime in code units for an electron at p=1 (units of m_p*c) and ub=1.  Same units at t and dt.