恆星質子融合

Solar pp Fusion

俞慎曦(Shen-Hsi Yu)

指導教授 ： 陳俊瑋

國立臺灣大學/理學院/物理研究所/碩士(2011年)

https://doi.org/10.6342/NTU.2011.00626

摘要

太陽標準模型(SSM)是一個用來描述太陽的模型。這個模型需要很多條件，像是發光度、半徑、組成、反應速率等等。在這論文裡，我們感興趣的是質子融合的反應速率。質子融合是質子反應鏈中第一個反應。對我們來說這個反應速率是很重要的，我們希望可以降低它的不確定性。反應速率是正比截面積的熱平均，包含一些穿遂庫倫的因子還有一些能量的關係。核反應的能量尺度大部分是MeV，而在太陽中心的溫度大約是10^7K或1keV。所以我們可做低能量的展開。在回顧文章SolarFusionII[1]中提到，以因次分析來看平方項的貢獻大概會是1%左右，而這個貢獻已經與整體的不確定性可相比。一般的文獻裡的式子大部分都只展開到線性項，我們展開反應速率到E^2項，希望可以得到一個≲1%的不確定性，然後可以更好的限制SSM。

關鍵字

太陽標準模型 ； 反應速率 ； 質子融合 ； 質子反應鏈

並列摘要

The solar standard model(SSM) is a model that describes the sun. There
are many inputs that we need, such as luminosity, radius, compositions and
reaction rate, etc. In the thesis we are interested in the solar pp fusion re-
action rate. The reaction rate is proportional to the thermal average of cross
section that contains Coulomb barrier penetration factor and some energy de-
pendence. Typical energy scale for nuclear reaction is of the order of MeV,
but in the center of the sun the typical temperature is about 10^7 K or 1 keV.
So we can do low energy expansion. pp fusion is the first reaction of pp chain
in the sun. The reaction rate is important to us, so we want to reduce the
uncertainty of the rate. In the review article Solar Fusion II[1], which pointed
out that dimensionally the quadratic term would enter at the level of ∽ 1%
for temperatures characteristic of the solar center. And this is now compa-
rable to the overall error. The expansions in the references are mostly only
up to linear term. We expand it to the quadratic term, aiming to reduce the
uncertainty to about 1%, and constrain the SSM better.

並列關鍵字

Solar standard model ； reaction rate ； pp fusion ； pp chain

參考文獻

[2] J. N. Bahcall and R. M. May, Astrophys. J. 155, 501 (1969).

[6] J. N. Bahcall, Nucl. Phys. 75, 10 (1966).

[7] Donald. D. Clayton, Principles of Stellar Evolution and Nucleosynthesis (McGraw-

Hill, Inc., 1968).

[1] E. G. Adelberger et al., arXiv:1004.2318 [nucl-ex].