Generalized Lawson criterion for magnetic fusion applications in space

Review of Nuclear Thermal Propulsion Systems

“…around 2025 [6]. A fusion NTP uses a thermonuclear fusion power source to heat up the working medium [19,[67][68][69][70][71][72]. Fusion is complementary to fission: instead of splitting one heavy atom core, fusion joins two lighter, separate cores into a single one.…”

“…radiologic waste, is considerably reduced in comparison to fission waste. The remaining three reactions have considerably less radiologic issues and are nominally aneutronic [71,[77][78][79][80]. This is -beside the significantly larger yield of energy and rich abundance of most fusion fuels in the solar system [67] -a decisive advantage of fusion among nuclear power sources.…”

“…Magnetically Confined Fusion Propulsion (MCFP) is a thermal propulsion concept currently investigated in Europe [19,[70][71][72]79]. The power is provided by the excessively hot magnetically confined fusion plasma.…”

“…MCFP systems of the first type are called Ash Drives (AD), of the latter Working Gas Drives (WGD). In both cases, the propulsion system relies on the fusion plasma whose operation is defined by the fusion criterion yielded by an energy and particle balance from which the characteristic triple product n T i E i τ can be calculated [71]. The triple product is made up of the first species' ions' particle density n i , the energy confinement time τ E , and the ions' temperature T i .…”

“…The major advantage the advanced pairings promise is a considerable reduction in neutron radiation and hence lightweight shields. However, investigations [71,80] showed that only D-3 He is worthwhile as a fuel in MCFP. Estimated propulsive data based on the MCFP models is documented in Table 11.…”