In reply to Robert Lynn's message of Thu, 13 Sep 2012 16:46:45 +0100: Hi, [snip] >One of the cool things about Ni-H LENR is that it has the potential to make >Bussard Ramjets more feasible (assuming it is H-H fusion as now seems most >likely). > >A Bussard Ramjet is a Rocket that scoops up hydrogen from the interstellar >medium using a vast magnetic and/or electrostatic field, then fuses it and >fires it out the back. The concept has always had a major flaw in that >hydrogen is nearly fusion-proof in conventional hot fusion except as part >of Carbon-Nitrogen fuel cycle. > >Even if that whole fusion reaction happened in a LENR cell and the power >conversion requires a heat engine the energy could still be used to drive a >particle accelerator that accelerated the ash (Helium?) out the back. You >would essentially never run out of fuel (so long as your LENR lattice >does't get used up), so possibly much faster trips to the stars without the >requirement for ridiculously large exotic (deuterium, lithium or He3) fuel >storage tanks. > >Speed might still be limited to a few % of c, but even that looks pretty >good from where we are standing now, as they can also be used for >decelleration and Bussard LENR ramjet ships might be a lot cheaper and more >compact than what was hither-to thought possible.
If the ratio of D/H is the same in interstellar gas as it is in water, then the average energy available per Hydrogen atom, from H+D -> He3 is 857 eV, which is higher than current chemical fuels by a factor of about 100. Hence the Bussard Ramjet principle has never had a problem. BTW you can create an electrical equivalent of the Bussard Ramjet, by shooting a beam of electrons ahead of the rocket. These attach themselves to hydrogen atoms forming negative ions which are then attracted to the positive charge left on the rocket when the electrons were ejected, thus "sucking" the ions into the rocket. The "sucking" action also imparts momentum to the rocket, in addition to the momentum acquired by ejecting fast particles out the rear. (The momentum lost by ejecting the electrons forward is only 2-3% of that acquired by sucking the ions in, due to the huge difference in mass). Regards, Robin van Spaandonk http://rvanspaa.freehostia.com/project.html
