How Does Inelastic Collision Facilitate Ionization and Excitation in Plasma?

[VulpineNinja]

1. Explain why it is important for inelastic equation to occur in a plasma in order for process such as ionization and excitation to happen.

2. 1/2(m1u1^2) = 1/2(m1)(v1^2 + u1^2 sin^2(theta)) + 1/2(m2v2^2) + (delta)U3. According to the inelastic equation above, in order for ionization and excitation to happen there should be an energy loss. And it is possible for atom to get excited or release electrons if another electron collides with the atom in inelastic equation. Which means that m1 must be smaller than m2

Sorry I don't have any software to write the equation clearly.
Anyways, I'm not sure how am I supposed to answer the question (should I explain the process based on the equation to prove my statement?), or that if my answer is accurate enough. Like, how do I relate with the loss of energy, (delta)U?
And furthermore, what makes inelastic collision (in plasma) more important than elastic?

 

[Delta2]

I guess ionization and excitation require some energy in order to happen and that energy is the loss in the kinetic energy (delta)U.