Alex H.Y. Cheung

    Graduate Student                                                                 

    Contact info: 

    Phone: (949) 824 -3784                                                                                    
    Fax: (949) 824 - 8585
    Email: ahcheung@uci.edu

    Rm 3111, Engineering Gateway
    Department of Mechanical and Aerospace Engineering            
    University of California, Irvine
    CA 92697-3975

    Faculty Advisors:

        Professor F. Liu

        Dr. F. J. Wessel

    Research Interest:                                                                               

    Classes served as Teaching Assistant:

        MAE 10, Introduction to Computer Programming, Fortran (Fall 2002, Fall 2003)
        MAE 80, Engineering Dynamics (Winter 2003)
        MAE 120, Fundamental Heat Transfer (Spring 2003)
        MAE 130B, Introduction to Viscous and Compressible Flows (Winter 2004)
        MAE 146, Astronautics (Currently)

    My Resume (pdf)

    Current Project:

My research involves adapting nuclear fusion as a power source for space propulsion. This particular fusion is called the Colliding Beam Fusion Reactor (CBFR). The main goal is to propose a design which would enable utilization of the nuclear reactor onboard a manned spacecraft; and the main objective is to provide means to evaluate system tradeoffs, predict performance and in doing so, obtain an optimal design, along with operating parameters. 

Figure shows how CBFR works

 The CBFR, first conceived by Professor N. Rostoker, et. al,  is a magnetic confinement system that avoids the typical anomalous transport (refers to all processes in which loss of particles or energy takes place - it is due to a variety of instabilities that lead to turbulence) that plagues current reactor designs. The reactor is compact with good accessibility and low maintenance costs. Most of the technologies needed to evaluate this concept exist, or could become available with simple engineering modifications to existing technologies. The device is based on an alternate confinement system called a Field Reversed Configuration (FRC) (a magnetic topology whereby the axial field inside the reactor is reversed [as compared to the externally applied field] by plasma currents) that confines beams of fuel ions. An essential component of the design is the use of advanced fuels (fuels with non-neutron producing primary reactions) such as Hydrogen and Boron-11. For this particular reaction, for example, the fusion products are all charged particles for which highly efficient direct conversion of the energy is feasible and neutron flux and associated on-site radioactivity is virtually non-existent.

Figure shows a conceptual design of the CBFR propulsion system.

Main Advantages of the CBFR:

1. Simple magnet setup with no toroidal field and, thus, only solenoidal magnetic coils like a mirror.                                
2. Possibility of direct energy converters at the ends.
3. Closed magnetic field region for confinement of fuel.
   Natural divertor outside the separatrix:
   o     Allows for extraction of charged fusion products.
   o     Prevents formation of scrape-off-layer.
   o     Subdued heat conduction due to vacuum layer outside of separatrix.
4. High "Beta" configuration:
   o     Allows use of advanced fuel.
   o     High power density.
   o     Better fuel burnup due to existence of magnetic field null:        non-adiabatic ions are available over a wide range of energies that pass through the null field surface periodically (even if they have quite different mass or charge) and thereby increase the fusion probability.
5. Majority of high energy particles: better stability and slower transport over the entire spectrum of turbulence.
   

    Publications:

       A. Cheung, M. Binderbauer, F. Liu, A. Qerushi, N. Rostoker, and F.J. Wessel,  "Colliding Beam Fusion Reactor Space Propulsion System" in Proceedings of the Space Technology & Applications International Forum (STAIF-2004_, edited by M.S. El-Genk, AIP Conference Proceedings 699, pp. 354-361
       Download presentation (Powerpoint)

    Some Pictures:

        Graduation: Patrick and Alex
        Graduation: Family
        Labmates
        Soccer League Champions
        Water Ski!
        F117
        JSF baby!!
        Life's Motto
        You Gotta See this...   

        Useful Links:

    Last Update: April 10th, 2004

    © Alex Cheung 2004