## public subroutine applySrc_chargeDensity_2ndOrd(fun, inState, outState, neigh, auxField, nPdfSize, iLevel, varSys, time, phyConvFac, derVarPos)

Update state with source variable "ChargeDensity" with 2nd order
integration of source Term.
Refer to Appendix in PhD Thesis of K. Masilamani
"Coupled Simulation Framework to Simulate Electrodialysis Process for

Where \rho_e is the charge density
KM: LBE solves potential equation of form
where
S = \frac{\rho_e}{\epsilon_r \epsilon_0}
Simuilar to derive routine but it updates the state whereas derive
is used for tracking.

This subroutine's interface must match the abstract interface definition
proc_apply_source in derived/mus_source_type_module.f90 in order to
be callable via applySrc function pointer.

### Arguments

Type | Intent | Optional | Attributes | | Name | |

class(mus_source_op_type), |
intent(in) |
| | :: |
**fun** | Description of method to apply source terms |

real(kind=rk), |
intent(in) |
| | :: |
**inState**(:) | input pdf vector |

real(kind=rk), |
intent(inout) |
| | :: |
**outState**(:) | output pdf vector |

integer, |
intent(in) |
| | :: |
**neigh**(:) | connectivity Array corresponding to state vector |

real(kind=rk), |
intent(in) |
| | :: |
**auxField**(:) | auxField array |

integer, |
intent(in) |
| | :: |
**nPdfSize** | number of elements in state Array |

integer, |
intent(in) |
| | :: |
**iLevel** | current level |

type(tem_varSys_type), |
intent(in) |
| | :: |
**varSys** | variable system |

type(tem_time_type), |
intent(in) |
| | :: |
**time** | Point in time at which to evaluate the variable. |

type(mus_convertFac_type), |
intent(in) |
| | :: |
**phyConvFac** | Physics conversion factor for current level |

type(mus_derVarPos_type), |
intent(in) |
| | :: |
**derVarPos**(:) | position of derived quantities in varsys |

## Variables

Type | Visibility | Attributes | | Name | | Initial | |

type(mus_varSys_data_type), |
private, | pointer | :: |
**fPtr** | | | |

real(kind=rk), |
private | | :: |
**rhs**(fun%elemLvl(iLevel)%nElems) | | | |

real(kind=rk), |
private | | :: |
**rhs_Fac** | | | |

integer, |
private | | :: |
**nElems** | | | |

integer, |
private | | :: |
**iElem** | | | |

integer, |
private | | :: |
**iDir** | | | |

integer, |
private | | :: |
**QQ** | | | |

integer, |
private | | :: |
**nScalars** | | | |

integer, |
private | | :: |
**posInTotal** | | | |

integer, |
private | | :: |
**statePos** | | | |