The Trojan Horse Astrophysicists have problems figuring out the details of fusion reactions in stars and gas clouds because of the presence of “electron screening” out in space. In the lab, electron screening cannot be simulated to derive laboratory fusion cross section measurements. It was systematically observed that the presence of the electronic clouds around the interacting ions in the measurements of nuclear reaction cross sections at astrophysical energies of about .1 to 100,000 max electron volts gives rise to an enhancement of the astrophysical S(E)-fusion cross section factor as lower and lower astronomical energies are explored.
Moreover, at present such an screening effect is not well understood as the value of the potential for screening extracted from these measurements is much higher than the upper limit of theoretical predictions (adiabatic limit). Since this electron screening potential in laboratory measurement is far different from that occurring in stellar plasmas, there is the high degree of interest in astrophysics surrounding the so-called “bare nucleus cross section”. This quantity can only be extrapolated in direct measurements. These are the reasons that led to a considerable growth on interest in a work around indirect measurement techniques and in particular the Trojan Horse Method (THM) [ http://arxiv.org/pdf/nucl-th/0401054.pdf ]. THM is a method used to simulate the pre stellar and stellar electron screening environments in the lab. If electron screening is important in LENR, THM might also work well in simulating nuclear reactions in LENR. Here is the Astrophysicists’ screening problem as follows: Coulomb-barrier: Energy = 1 MeV Astrophysical energy available in the stellar environment = .1 to 100 keV How can a significant amount of nuclear reactions proceed in space when the Coulomb-potential is far too high? Solution: quantum mechanical penetration probability of the Coulomb-barrier through coulomb screening. See: http://www.mpa-garching.mpg.de/lectures/ADSEM/SS04_Marek.pdf See the graphs in slide 21 If your interest is peaked, for more details see another slide show at: http://www.google.com/url?sa=t&rct=j&q=&esrc=s&frm=1&source=web&cd=9&ved=0CGwQFjAI&url=http%3A%2F%2Fcyclotron.tamu.edu%2Fcssp10%2Findex_files%2Fpresentations%2Ftuesday2%2Fsparta.ppt&ei=mnn_T8jCFoS30AGpnbmrBw&usg=AFQjCNGF7_pKQUKqoUiCxEP2LHuNlKDN9A&sig2=EpPGIal65GeLeXLmfYEhjg Cheers: Axil
