B.B.C. Article
Researchers at a US lab have passed a crucial milestone on the way to their ultimate goal of achieving self-sustaining nuclear fusion.
Harnessing fusion - the process that powers the Sun - could provide an unlimited and cheap source of energy.
But to be viable, fusion power plants would have to produce more energy than they consume, which has proven elusive.
Now, a breakthrough by scientists at the National Ignition Facility (NIF) could boost hopes of scaling up fusion.
NIF, based at Livermore in California, uses 192 beams from the world's most powerful laser to heat and compress a small pellet of hydrogen fuel to the point where nuclear fusion reactions take place.

(Continues)

Lawrence Livermore claims a milestone in laser fusion

A tiny pellet of deuterium and tritium released more energy than it absorbed from the National Ignition Facility’s bank of 192 lasers.

David Kramer

Lawrence Livermore National Laboratory (LLNL) announced today that it has produced a fusion reaction in the laboratory that yielded more energy than was absorbed by the fuel to initiate it.

...

The lab is still analyzing the results from the shot. It’s not yet known which or what combination of advances to the targets, laser pulse lengths, or other variables led to the leap in performance. Some of the instruments were saturated by the unexpected yield of the reaction. A few that are used in the target chamber for other, non-ignition experiments will need repair.

Herrmann acknowledged that the announcement deviates from the standard practice of peer-reviewed publication. But the results, he says, were leaking, “so we wanted to put it out so people could discuss the facts.”

Editor’s note, 17 August: The first sentence was updated to clarify that the fusion reaction did not meet the National Academy’s definition of ignition.

Sgt Kelly wrote:The sun is a star. Stars do run out of fuel and die (because the excess energy is radiated into space allowing you - among other things - to read this text). This can happen in a variety of ways depending on the composition of the star. Some of these ways include the star exploding violently which is known as a supernova.

IIRC the sun will expand towards the end of the current stage of its lifecycle and engulf the surrounding planets, including earth. The planet will become inhospitable to life long before that of course due to the increasing proximity of the sun's surface.

I wouldn't worry about that though. This is so far in the future that no human will be around to see it. We will be long extinct by then. In fact all traces of our existence will have been long wiped out as the atoms that make up everything we have done will have been recycled through the earth's molten core several times.

As you can tell I only know the general gist of it, someone will surely be able to give you more details.

Sgt Kelly wrote:This is so far in the future that no human will be around to see it..

Adco wrote:If fusion produces more energy than it consumes, and our sun is powered by this process, is the sun ever going to every use up all it's fuel source?

I'm sure that's not the case and I'm looking at this incorrectly.

The theory that proton–proton reactions are the basic principle by which the Sun and other stars burn was advocated by Arthur Eddington in the 1920s. At the time, the temperature of the Sun was considered to be too low to overcome the Coulomb barrier. After the development of quantum mechanics, it was discovered that tunneling of the wavefunctions of the protons through the repulsive barrier allows for fusion at a lower temperature than the classical prediction.

In 1939, Hans Bethe attempted to calculate the rates of various reactions in stars. Starting with two protons combining to give deuterium and a positron he found what we now call Branch II of the proton-proton chain. But he did not consider the reaction of two 3He nuclei (Branch I) which we now know to be important.[6] This was part of the body of work in stellar nucleosynthesis for which Bethe won the Nobel Prize in Physics in 1967.

hackenslash wrote:Bashed something together.

Let's Stick Together...

Hermit wrote:It is huge. Unfortunately almost everyone ignores its existence. It's the difference between Q-plasma and Q-total.

A major breakthrough has been announced by US scientists in the race to recreate nuclear fusion.

Physicists have pursued the technology for decades as it promises a potential source of near-limitless clean energy.

On Tuesday researchers confirmed they have overcome a major barrier - producing more energy from a fusion experiment than was put in.

On the question of how long before we could see fusion being used in power stations, Dr Budil, the LLNL director, said there were still significant hurdles but that: "with concerted efforts and investment, a few decades of research on the underlying technologies could put us in a position to build a power plant".

This is progress from when scientists used to say 50-60 years in answer to that question.