## Convert_to_HydroBase: A Module for Converting IllinoisGRMHD variables into HydroBase variables, for Analysis

Date: 2015-10-12 12:00:00 -0600 (Mon, 12 Oct 2015) 

Abstract

IllinoisGRMHD and HydroBase variables are incompatible; The former uses 3-velocity defined as ${v}^{i}={u}^{i}∕{u}^{0}$, and the latter uses the Valencia formalism definition of ${v}^{i}$.

Define the Valencia formalism’s definition of ${v}^{i}$ to be ${W}^{i}$”, and IllinoisGRMHD’s definition ”${v}^{i}$ Then

 ${W}^{i}=\left({v}^{i}+{\beta }^{i}\right)∕\left(\alpha \right),$ (1)

which comes from Eq 11 in the IllinoisGRMHD code announcement paper:
http://arxiv.org/pdf/1501.07276.pdf.

Similarly,

 ${v}_{i}=\left(\alpha \right){W}^{i}-{\beta }^{i}$ (2)

In addition, IllinoisGRMHD needs the A-fields to be defined on staggered grids, and HydroBase does not yet support this option. The staggerings are defined in Table 1 of the IllinoisGRMHD code announcement paper:
http://arxiv.org/pdf/1501.07276.pdf (page 15).

The long-term goal should be to adjust HydroBase and IllinoisGRMHD so that this thorn is no longer necessary.

### 1 Parameters

 convert_to_hydrobase_every Scope: private INT Description: How often to convert IllinoisGRMHD primitive variables to HydroBase (Valencia formulation) primitive variables? Needed for some ET-based diagnostics. NOT needed for pure IllinoisGRMHD runs. Range Default: (none) 0:* zero (disable) or positive (every N iterations)

 gamma_th Scope: shared from ILLINOISGRMHD REAL

### 2 Interfaces

#### General

Implements:

convert_to_hydrobase

Inherits:

grid

hydrobase

illinoisgrmhd

### 3 Schedule

This section lists all the variables which are assigned storage by thorn WVUThorns/Convert_to_HydroBase. Storage can either last for the duration of the run (Always means that if this thorn is activated storage will be assigned, Conditional means that if this thorn is activated storage will be assigned for the duration of the run if some condition is met), or can be turned on for the duration of a schedule function.

NONE

#### Scheduled Functions

CCTK_INITIAL

convert_to_hydrobase

convert illinoisgrmhd-native variables to hydrobase

 After: settmunu Language: c Type: function

CCTK_ANALYSIS

convert_to_hydrobase

convert illinoisgrmhd-native variables to hydrobase

 After: ml_bssn_evolcalcgroup Before: compute_bi_b2_poyn_fluxet particle_traceret volumeintegralgroup convert_to_mhd_3velocity Language: c Options: global-early loop-local Type: function