Research Interests

1. ExB probe

I am interested in advancing this plasma diagnostic probe. I think this probe can be one single probe for ion energy measurement. ExB probe can do species-specific measurement that RPA cannot do. ExB probe can be made as light as a few lbs, which is difficult for QMS. There is a lot of work needed to make it, but I am willing to solve these challenges. 

2. RF cathode

The EP community is moving toward alternative propellant EP systems (ABEP, ISRU, etc). There are several approaches, but if you want to keep using conventional electrostatic thrusters such as gridded ion engines or Hall effect thrusters, a development of an oxygen-compatible cathode is necessary. RF cathode is a promising technology, yet we don't know what's happening very much. We need to have a deeper understanding of it, which will accelerate its technological advancement.

3. Sheath and Bohm Criterion

When you start studying a plasma, the concept of the sheath is introduced in a relatively early stage. In fact, when you try to use a plasma, you must think about a sheath, because a sheath appears when you "touch" a plasma with something. As you study a sheath, you probably learn about a pre-sheath and the Bohm criterion. An ion is accelerated in a pre-sheath and reaches a Bohm velocity (v_B = √{k_B*T_e/m_i} where k_B = Boltzmann constant, T_e = electron temperature, and m_i = ion mass).
In a 1D world where the Bohm criterion is derived,  a Bohm velocity = a Bohm speed. How about in a 2D and 3D world? When an ion reaches at sheath edge, does it have some incident angle? If so, is it speed equal to the Bohm velocity? Or, do all the ions enter the sheath with no incident angle?