Reactions with the background plasma

The hydrocarbon molecules/ions, can undergo a multitude of state changing reactions with the background plasma. The types of reactions possible depend on whether the hydrocarbon is a neutral or ion, and whether it collides with an ion or electron from the plasma. The most important reactions (those with the largest cross sections at reactor relevant plasma temperatures) are shown below.

Neutral reactions

Collisions with plasma ions (D+ or T+)

Charge exchange

Collisions with electrons (e-)

Ionization
Dissociative ionization
Dissociation

Ion reactions

Dissociative recombination

Reaction rate coefficients

Each reaction type for each species has its own unique reaction rate coefficient. The rate of reactions occuring (in inverse seconds) is given by this rate coefficient times the plasma density. Typically, rate coefficients must be calculated from the cross section for the reaction, integrated over a Maxwellian temperature distribution about a given plasma temperature.

where the Maxwellian distribution function is given by

This is done in our code as one of the initial calculations, before any particles are simulated.