Read name of the ionization species

Source/Particles/Collision/BinaryCollision/DSMC/DSMCFunc.H

@@ -205,7 +205,10 @@ public:
 
 private:
  amrex::Vector<ScatteringProcess> m_scattering_processes;
+ amrex::Vector<ScatteringProcess> m_ionization_processes;
  amrex::Gpu::DeviceVector<ScatteringProcess::Executor> m_scattering_processes_exe;
+ amrex::Gpu::DeviceVector<ScatteringProcess::Executor> m_ionization_processes_exe;
+
  bool m_isSameSpecies;
 
  Executor m_exe;

Source/Particles/Collision/BinaryCollision/DSMC/DSMCFunc.cpp

@@ -52,7 +52,24 @@ DSMCFunc::DSMCFunc (
  WARPX_ALWAYS_ASSERT_WITH_MESSAGE(process.type() != ScatteringProcessType::INVALID,
  "Cannot add an unknown scattering process type");
 
- m_scattering_processes.push_back(std::move(process));
+ // if the scattering process is ionization get the secondary species
+ // only one ionization process is supported, the vector
+ // m_ionization_processes is only used to make it simple to calculate
+ // the maximum collision frequency with the same function used for
+ // particle conserving processes
+ if (process.type() == ScatteringProcessType::IONIZATION) {
+ WARPX_ALWAYS_ASSERT_WITH_MESSAGE(!ionization_flag,
+ "Background MCC only supports a single ionization process");
+ ionization_flag = true;
+
+ std::string secondary_species;
+ pp_collision_name.get("ionization_species", secondary_species);
+ m_species_names.push_back(secondary_species);
+
+ m_ionization_processes.push_back(std::move(process));
+ } else {
+ m_scattering_processes.push_back(std::move(process));
+ }
  }
 
  const int process_count = static_cast<int>(m_scattering_processes.size());