Related topics: plasma

Image: Hubble views star nearing its end

This image from the NASA/ESA Hubble Space Telescope shows NGC 5307, a planetary nebula that lies about 10,000 light-years from Earth. It can be seen in the constellation Centaurus (the Centaur), which can be seen primarily ...

Star nearing death offers a preview of our Sun's fate

An international team of astronomers has witnessed a rare dynamic event foreshadowing the death of a red giant star for the first time – a discovery that reinforces predictions about our Sun's ultimate demise.

Measuring the laws of nature

A physical constant, which is of great importance for basic research, has now be re-measured, with much higher precision than ever before.

Earth to Mars in 100 days: The power of nuclear rockets

The solar system is a really big place, and it takes forever to travel from world to world with traditional chemical rockets. But one technique developed back in the 1960s might provide a way to shorten our travel times dramatically: ...

Hubble captures elusive, irregular galaxy

This image shows an irregular galaxy named IC 10, a member of the Local Group—a collection of over 50 galaxies in our cosmic neighborhood that includes the Milky Way.

New device in Z machine measures power for nuclear fusion

If you're chasing the elusive goal of nuclear fusion and think you need a bigger reactor to do the job, you first might want to know precisely how much input energy emerging from the wall plug is making it to the heart of ...

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Nuclear fusion

In nuclear physics and nuclear chemistry, nuclear fusion is the process by which multiple like-charged atomic nuclei join together to form a heavier nucleus. It is accompanied by the release or absorption of energy, which allows matter to enter a plasma state.

The fusion of two nuclei with lower mass than iron (which, along with nickel, has the largest binding energy per nucleon) generally releases energy while the fusion of nuclei heavier than iron absorbs energy; vice-versa for the reverse process, nuclear fission. In the simplest case of hydrogen fusion, two protons have to be brought close enough for their mutual electric repulsion to be overcome by the nuclear force and the subsequent release of energy.

Nuclear fusion occurs naturally in stars. Artificial fusion in human enterprises has also been achieved, although has not yet been completely controlled. Building upon the nuclear transmutation experiments of Ernest Rutherford done a few years earlier, fusion of light nuclei (hydrogen isotopes) was first observed by Mark Oliphant in 1932; the steps of the main cycle of nuclear fusion in stars were subsequently worked out by Hans Bethe throughout the remainder of that decade. Research into fusion for military purposes began in the early 1940s as part of the Manhattan Project, but was not successful until 1952. Research into controlled fusion for civilian purposes began in the 1950s, and continues to this day.

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