8,479 research outputs found
The need for isotopic data on refractory elements in the solar wind
The Sun accounts for the bulk of material in the solar system. Information on the isotopic composition of elements in the solar wind is therefore essential for an understanding of the contribution made by each nucleogenetic component that has been identified in meteorites. Recent work suggests that isotopic data on the solar wind may also help us to understand the physical process that is concentrating light elements at the solar surface. Refractory and volatile elements would behave alike under the conditions of solar fractionation. Prolonged exposure of foils at 1AU from the sun would be a relatively inexpensively way to collect the quantity of solar wind implanted refractory elements needed to test this hypothesis
Bath-induced correlations in an infinite-dimensional Hilbert space
Quantum correlations between two free spinless dissipative distinguishable
particles (interacting with a thermal bath) are studied analytically using the
quantum master equation and tools of quantum information. Bath-induced
coherence and correlations in an infinite-dimensional Hilbert space are shown.
We show that for temperature T > 0 the time-evolution of the reduced density
matrix cannot be written as the direct product of two independent particles. We
have found a time-scale that characterizes the time when the bath-induced
coherence is maximum before being wiped out by dissipation (purity, relative
entropy, spatial dispersion, and mirror correlations are studied). The Wigner
function associated to the Wannier lattice (where the dissipative quantum walks
move) is studied as an indirect measure of the induced correlations among
particles. We have supported the quantum character of the correlations by
analyzing the geometric quantum discord.Comment: 13 pages, 5 figures. arXiv admin note: substantial text overlap with
arXiv:1512.0870
Observational confirmation of the Sun's CNO cycle
Gamma rays from a solar flare in Active Region 10039 on 23 July 2002 with the
RHESSI spacecraft spectrometer indicate that the CNO cycle occurs at the solar
surface, in electrical discharges along closed magnetic loops. At the two feet
of the loop, H ions are accelerated to energy levels that surpass Coulomb
barriers for the C-12[H-1, gamma]N-13 and N-14[H-1, gamma]O-15 reactions. First
x-rays appear along the discharge path. Next annihilation of positrons from
N-13 and O-15 [half-life = 10 m and 2 m] produce bright spots of 0.511 MeV
gammas at the loop feet. As C-13 increases from positron decay of N-13, the
C-13[He-4, n]O-16 reaction produces neutrons and then the 2.2 MeV emission line
appears from n-capture on H-1. These results suggest that the CNO cycle changed
the N-15/N-14 ratio in the solar wind and at the solar surface over geologic
time, and this ratio may contain an important historical record of climate
changes related to sunspot activity.Comment: 9 pages, 21 references, 2 figures show x-rays and gamma-rays from
nuclear reactions in a solar-flare-induced electrical discharge. Replaced to
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