科技科普：氢弹和原子弹有什么分别

North Korea claimed that a nuclear blast on Sunday was a big advance from its previous five tests because it had successfully detonated a hydrogen bomb. But some experts suspect the North may have tested a “boosted” atomic bomb.

朝鲜声称，与它之前的五次核试验相比，周日的核爆炸是个巨大进步，因为它成功地引爆了一枚氢弹。但有些专家猜测，朝鲜可能只是试验了一枚“加强版”原子弹。

How are a hydrogen bomb and a regular atomic bomb different? And why would that matter to the United States and its allies? Here’s what the experts say.

氢弹和常规原子弹有什么区别呢？为什么那对美国及其盟国关系重大呢？下面是专家们的解释。

How do nuclear weapons work?

核武器是如何产生效果的？

Nuclear weapons trigger an explosive reaction that shears off destructive energy locked inside the bomb’s atomic materials.

核武器引发的爆炸反应能释放炸弹原子材料中的破坏性能量。

The first atomic weapons, like those dropped by the United States on the Japanese cities of Hiroshima and Nagasaki in World War II, did that with fission - splitting unstable uranium or plutonium atoms so that their subatomic neutrons fly free, smash up more atoms and create a devastating blast.

早期的原子弹，比如美国在“二战”期间向日本城市广岛和长崎投放的原子弹，就是通过裂变引发爆炸--分裂不稳定的铀或钚原子，使它们的亚原子中子自由移动，撞击更多原子，制造灾难性爆炸。

How is a hydrogen bomb different?

氢弹有何不同？

A hydrogen bomb, also called a thermonuclear bomb or an H-bomb, uses a second stage of reactions to magnify the force of an atomic explosion.

氢弹又称热核炸弹或H弹，它利用第二阶段的反应，增强原子弹爆炸的威力。

That stage is fusion - mashing hydrogen atoms together in the same process that fuels the sun. When these relatively light atoms join together, they unleash neutrons in a wave of destructive energy.

第二阶段是聚变，就是将氢原子聚合到一起，这个过程与太阳产生能量的过程相同。当这些相对较轻的原子聚合到一起时，它们以破坏性能量波的方式释放中子。

A hydrogen weapon uses an initial nuclear fission explosion to create a tremendous pulse that compresses and fuses small amounts of deuterium and tritium, kinds of hydrogen, near the heart of the bomb. The swarms of neutrons set free can ramp up the explosive chain reaction of a uranium layer wrapped around it, creating a blast far more devastating than uranium fission alone.

氢弹利用起初的核裂变爆炸，制造出巨大脉冲，压缩和聚合炸弹中心的少量重氚和氚--它们是氢。释放出的中子群可以增强包裹在外面的铀层的爆炸连锁反应，其爆炸的破坏性要比铀裂变强得多。

The United States tested a hydrogen bomb at Bikini Atoll in 1954 that was over 1,000 times more powerful than the atomic bomb dropped on Hiroshima in 1945. Britain, China, France and Russia have also created hydrogen bombs.

1954年，美国在比基尼环礁试验了一枚氢弹，它比1945年投放到长崎的原子弹的威力大1000多倍。英国、中国、法国和俄罗斯也已经制造出了氢弹。

What would a successful hydrogen test mean?

一次成功的氢弹试验意味着什么？

North Korea claimed that it successfully staged a hydrogen bomb test in January 2016, but experts were skeptical.

2016年1月，朝鲜声称成功地进行了一次氢弹试验，但专家们对此表示怀疑。

A successful test this time would show that the North’s nuclear program has become more sophisticated and that the country is closer to making an atomic warhead that could be fitted on a long-range missile able to strike the mainland United States.

如果这次的试验成功，它将表明朝鲜的核计划变得更加先进，该国更接近能够制造出可以装在打击美国本土的远程导弹上的核弹头。

The underground blast, which caused tremors felt in South Korea and China, was the first by the North to surpass the destructive power of the bombs dropped on Hiroshima and Nagasaki.

韩国和中国都能感受到这次地下爆炸所产生的震动，这是朝鲜制造的炸弹首次超过在长崎和广岛投放的核弹威力。

If the North has the capability to build a hydrogen bomb, it could open the way to making warheads that pack much more destructive power in a smaller space. It could also enable North Korea to enhance the threat from its limited stocks of enriched uranium.

如果朝鲜能够制造氢弹，那么就打开了在更小的空间里安装破坏力大得多的弹头的通道。朝鲜也因此能够提高它有限的浓缩铀储备的威胁。

What will experts look for?

专家们要寻找什么？

Analysts who advise governments on nuclear weapons will study the shock waves from the blast measured by monitoring stations. They will also look for clues from traces of nuclear gases that could float into the atmosphere.

为政府提供核武器顾问的分析人士将研究监测站测到的爆炸冲击波。他们也将寻找飘浮到大气中的核气体的残留物。

Those traces may tell if this test was really a hydrogen bomb, or perhaps something less than a full-scale thermonuclear device. But it can take weeks for the gases to leak out and be detected.

通过这些残留物，可以判断出这次试验真的是氢弹试验，还是某种低于完整规模的热核设备的武器。不过，那些气体泄露到空气中并被监测到还需要数周时间。