16,447 research outputs found

    Conditions for plasma evolution to the\ strong general Woltjer-Taylor state

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    We find that the proof in the recent paper\textsuperscript{\cite{14}} can not justify the authors' conclusion. We provide a real proof that any state will eventually evolves to the Woltjer-Taylor state exponentially. However, this kind of evolution is is mainly due to Joule heat, which also makes the magnetic field vanishes exponentially. Zero Woltjer-Taylor states are not physically attractive. Instead of examine Δ\Delta, we introduce the quantity θ×B,B\theta_{\nabla \times \vec{B},\vec{B}} and RR to examine if the plasma reaches to the strong (general) Woltjer-Taylor state, and then derive the condition for the evolution to the strong/general Woltjer-Taylor state

    Advantages of the multinucleon transfer reactions based on 238U target for producing neutron-rich isotopes around N = 126

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    The mechanism of multinucleon transfer (MNT) reactions for producing neutron-rich heavy nuclei around N = 126 is investigated within two different theoretical frameworks: dinuclear system (DNS) model and isospin-dependent quantum molecular dynamics (IQMD) model. The effects of mass asymmetry relaxation, N=Z equilibration, and shell closures on production cross sections of neutron-rich heavy nuclei are investigated. For the first time, the advantages for producing neutron-rich heavy nuclei around N = 126 is found in MNT reactions based on 238U target. We propose the reactions with 238U target for producing unknown neutron-rich heavy nuclei around N = 126 in the future.Comment: 6 pages, 6 figure

    Systematic study of proton radioactivity of spherical proton emitters within various versions of proximity potential formalisms

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    In this work we present a systematic study of the proton radioactivity half-lives of spherical proton emitters within the Coulomb and proximity potential model. We investigate 28 different versions of the proximity potential formalisms developed for the description of proton radioactivity, α\mathcal{\alpha} decay and heavy particle radioactivity. It is found that 21 of them are not suitable to deal with the proton radioactivity, because the classical turning points rinr_{\text{in}} cannot be obtained due to the fact that the depth of the total interaction potential between the emitted proton and the daughter nucleus is above the proton radioactivity energy. Among the other 7 versions of the proximity potential formalisms, it is Guo2013 which gives the lowest rms deviation in the description of the experimental half-lives of the known spherical proton emitters. We use this proximity potential formalism to predict the proton radioactivity half-lives of 13 spherical proton emitters, whose proton radioactivity is energetically allowed or observed but not yet quantified, within a factor of 3.71.Comment: 10 pages, 5 figures. This paper has been accepted by The European Physical Journal A (in press 2019
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