This project proposal was submitted on September 7, 2012 and the announcement for the awardees were made on January 11, 2013. This project officially began on March 15, 2013. It has a duration of 3 years with a total budget of 390k TL including the payment for the department and the PTI. This project promises the manufacturing and testing of a hollow cathode and a numerical modeling effort for the cathode insert region plasma.

Ion engines and Hall effect thrusters need a cathode for two reasons. The first reason is to supply the electrons needed to ionize the neutral propellant gas. Ionization is needed, because the Hall effect thrusters and ion engines work on the principle of electromagnetic forces accelerating the charged particles of the propellant. In both the standard (Kauffman type) ion engines and the Hall effect thrusters the ionization of the propellant gas, thus the plasma generation, occurs with the process called electron-impact Ionization. For this ionization process, the required electrons are supplied by a hollow cathode. The second reason is to provide the electrons needed to neutralize the ion beam leaving the thruster, thus the satellite or spacecraft. This is needed to prevent the spacecraft from charging (thus preventing the propulsion systems continued operation). In terms of the performance and the operational life of both the Hall effect thrusters and the ion engines, the cathode material, physical configuration and the structure are of great importance.

This project will have two major parts, an experimental and a theoretical (modeling) part. On the experimental side, a lanthanum hexaboride (LaB6) hollow cathode to be used for the operation of an ion engine or a Hall effect thruster will be designed and manufactured. Lanthanum hexaboride has been chosen as the cathode insert material, because of its lesser sensitivity to impurities in the propellant gas and lesser sensitivity to humidity, and its better suitability to laboratory testing where exposure to atmosphere is common. In the development of the hallow cathode, the studies and designs at NASA’s Jet Propulsion Laboratory (JPL) will be used as a reference starting point. The target current values will be in the 0.5-3.0 Ampere range. In order to achieve the targeted cathode current levels, the propellant flow to the cathode will be adjusted. It is estimated that a 100W heater unit will be required to allow the starting of the cathode within 120 minutes. After the cathode starts its operation no other heater power would be required.

On the theoretical side a two dimensional axisymmetric numerical model of the discharge region of a hollow cathode will be developed. The driving physics inside orificed hollow cathodes is not well understood. Such a study will complement and aid the development effort of the cathode.

As part of this project it is possible to employ 3 graduate and 1 undergraduate students at a given time. Graduate students (Oguz Korkmaz, Sina Jahanbakhsh and Ali Enes Ozturk) and undergraduate student (Firat Sik) are being paid through this project’s budget.