Flightweight magnets for advanced power and propulsion applications

James N. Chapman*, John T. Lineberry, Harold J. Schmidt, Rodney S. Ruoff, Venkat Chandrasekhar, Dmytro A. Dikin, Ron J. Litchford, John W. Cole

*Corresponding author for this work

Research output: Contribution to conferencePaperpeer-review

1 Scopus citations


Advanced space and airborne-based propulsion and energy conversion systems require magnets. This is especially evident for a number of advanced concepts, including the following: Applications of magnetic nozzles Magnetohydrodynamic (MHD) acceleration to augment chemical rocket systems to achieve higher ISPs Both the generator and the accelerator in the AJAX type propulsion system MHD power generation systems such as needed for the nuclear powered space vehicle Power generation for auxiliary systems Flow modification systems for hypersonic aircraft and space vehicles while in the atmosphere Magnetic confinement of fusion reactions In most of these applications a very high magnetic field is needed for practical application. The weight of a magnet typically varies as the square of the field strength. Thus, the magnet could be too heavy for fruitful application in these systems unless magnets with weight reduced from the current ground based technology are developed. In this paper, we review the options for a fabricating a lightweight magnet. Among the technologies considered are lightweight conventional coils, low temperature superconducting coils, magnesium diboride coils, high temperature superconducting coils (both BSCCO and YBCO) and potential advanced conductor materials, especially carbon nanotubes. For each of these technologies an estimate of the weight of example magnets is presented. Coil weights are inversely proportional to engineering current density in the conductors. The stress containment structure for the magnet is a major contributor to the total weight. High current density contributes to lower stress containment structure because the magnet is smaller. To further minimize this structure weight, materials with a high strength to weight ratio are needed, e.g. carbon-carbon composites and carbon nanotube composites in the future For every conductor except room temperature superconductors, refrigeration to the required conductor operating temperature is a second major contributor to weight. The required refrigeration is a strong function of the temperature range over which the system must operate, increasing exponentially toward lower operating temperatures. Thus, the higher conductor operating temperature is for a given current density, the lower the refrigeration requirement and weight. Consequently, the most dramatic weight reductions for future magnets may utilize carbon nanotube conductors and structures made with carbon nanotube fibers, when successfully developed.

Original languageEnglish (US)
Number of pages10
StatePublished - 2004
Event42nd AIAA Aerospace Sciences Meeting and Exhibit - Reno, NV, United States
Duration: Jan 5 2004Jan 8 2004


Other42nd AIAA Aerospace Sciences Meeting and Exhibit
CountryUnited States
CityReno, NV

ASJC Scopus subject areas

  • Engineering(all)

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