Editing Antimatter rocket (section)

===Catalyzed fission/fusion or spiked fusion===

This is a hybrid approach in which antiprotons are used to [[Antimatter-catalyzed nuclear pulse propulsion|catalyze a fission/fusion reaction]] or to "spike" the propulsion of a [[fusion rocket]] or any similar applications.

The antiproton-driven [[Inertial confinement fusion]] (ICF) Rocket concept uses pellets for the [[Fusion power|D-T reaction]].  The pellet consists of a hemisphere of fissionable material such as [[Uranium|U<sup>235</sup>]] with a hole through which a pulse of antiprotons and positrons is injected. It is surrounded by a hemisphere of fusion fuel, for example deuterium-tritium, or lithium deuteride. Antiproton annihilation occurs at the surface of the hemisphere, which ionizes the fuel. These ions heat the core of the pellet to fusion temperatures.<ref name=NIAC98-02FR>{{cite report |first1=Terry |last1=Kammash |year=1998 |title=Antiproton Driven Magnetically Insulated Inertial Confinement Fusion (Micf) Propulsion System |url=http://www.niac.usra.edu/files/studies/final_report/361Kammash.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://www.niac.usra.edu/files/studies/final_report/361Kammash.pdf |archive-date=2022-10-09 |url-status=live |citeseerx=10.1.1.498.1830 }}</ref>

The antiproton-driven Magnetically Insulated Inertial Confinement Fusion Propulsion (MICF) concept relies on self-generated magnetic field which insulates the plasma from the metallic shell that contains it during the burn. The lifetime of the plasma was estimated to be two orders of magnitude greater than implosion inertial fusion, which corresponds to a longer burn time, and hence, greater gain.<ref name=NIAC98-02FR/>

The antimatter-driven [[aneutronic fusion|P-B<sup>11</sup>]] concept uses antiprotons to ignite the P-B<sup>11</sup> reactions in an MICF scheme. Excessive radiation losses are a major obstacle to ignition and require modifying the particle density, and plasma temperature to increase the gain. It was concluded that it is entirely feasible that this system could achieve I<sub>sp</sub>~10<sup>5</sup>s.<ref name=NASA7347634540>{{cite journal |last1=Kammash |first1=Terry |last2=Martin |first2=James |last3=Godfroy |first3=Thomas |title=Antimatter Driven P-B11 Fusion Propulsion System |journal=AIP Conference Proceedings |date=17 January 2003 |volume=654 |issue=1 |pages=497–501 |doi=10.1063/1.1541331 |bibcode=2003AIPC..654..497K |hdl=2027.42/87345 |hdl-access=free }}</ref>

A different approach was envisioned for [[AIMStar]] in which small fusion fuel droplets would be injected into a cloud of antiprotons confined in a very small volume within a reaction [[Penning trap]]. Annihilation takes place on the surface of the antiproton cloud, peeling back 0.5% of the cloud. The power density released is roughly comparable to a 1 kJ, 1 ns laser depositing its energy over a 200&nbsp;μm ICF target.<ref name=AIAA-99-2700>{{cite journal |last1=Lewis |first1=Raymond |last2=Meyer |first2=Kirby |last3=Smith |first3=Gerald |last4=Howe |first4=Steven |title=AIMStar - Antimatter Initiated Microfusion for pre-cursor interstellar missions |journal=35th Joint Propulsion Conference and Exhibit |year=1999 |doi=10.2514/6.1999-2700 |citeseerx=10.1.1.577.1826 }}</ref>

The [[ICAN-II]] project employs the antiproton catalyzed microfission (ACMF) concept which uses pellets with a molar ratio of 9:1 of D-T:U<sup>235</sup> for [[nuclear pulse propulsion]].<ref name=AIAA-1998-3589>[https://www.engr.psu.edu/antimatter/Papers/ICAN.pdf  "Antiproton-Catalyzed Microfission/Fusion Propulsion Systems for Exploration of the Outer Solar System and Beyond"] {{webarchive |url=https://web.archive.org/web/20140805152150/https://www.engr.psu.edu/antimatter/Papers/ICAN.pdf |date=August 5, 2014 }} G. Gaidos, R.A. Lewis, G.A. Smith, B. Dundore and S. Chakrabarti, AIAA Paper 1998-3589, July 1998</ref>