Constraints on the strength of a primordial magnetic field from big bang nucleosynthesis.
Constraints on the strength of a primordial magnetic field from big bang nucleosynthesis.
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对大爆炸核合成的原始磁场强度的限制。
DOI：
10.1103/physrevd.49.5006
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发表时间：
1993
期刊：
影响因子：
--
通讯作者：
J. Truran
中科院分区：
文献类型：
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作者：
Baolian Cheng;David N. Schramm;J. Truran
计算了磁场对大爆炸核合成（BBN）的影响，数值研究了磁场对轻元素丰度的影响。由此得到了与轻元素丰度观测相一致的原始磁场强度的上限。在标准BBN理论的框架中，原始磁场的最大强度，在尺度上大于10[sup 4] cm但小于BBN时期的事件视界（[类似于]1 min，[类似于]2[乘以]10[sup 12] cm），为[le]10[sup 11] G。这一限制被证明允许在重组时的磁场不强于[类似于]0.1 G的尺度[ge]10[sup 11] cm。我们的研究结果还强烈表明，在BBN时代，磁场强度[ital B][le]10[sup 13] G，磁场对轻元素原始丰度的影响主要是由反应速率在原始磁场的存在下，而不是由磁密度对膨胀率的影响。
The effects of magnetic fields on big bang nucleosynthesis (BBN) are calculated, and the impact on the abundances of the light elements are investigated numerically. An upper limit on the strength of primordial magnetic fields compatible with observations of light element abundances is thus obtained. In the framework of standard BBN theory, the maximum strength of the primordial magnetic fields, on scales greater than 10[sup 4] cm but smaller than the event horizon at the BBN epoch ([similar to]1 min, [similar to]2[times]10[sup 12] cm), is [le]10[sup 11] G. This limit is shown to allow magnetic fields at the time of recombination no stronger than [similar to]0.1 G on scales [ge]10[sup 11] cm. Our results also strongly indicate that, at the BBN epoch, and for field strengths [ital B][le]10[sup 13] G, the effects of magnetic fields on the primordial abundances of light elements are dominated by effects from reaction rates in the presence of primeval magnetic fields rather than by magnetic density effects on the expansion rate.