The word "fusion" has had many definitions over the last 100 years. In 2020, the word Fusion means "Fusion Power." Clean power for mankind's future is Fusion. The human pursuit of achievable Fusion is a noble undertaking. In both the previous sentences, the word Fusion was unarguably defined as Fusion Power. No one would misunderstand. The word Power no longer needs to follow Fusion. Power is understood to be the meaning of the word Fusion.
The definition of 'fusion' has morphed as the group of people using the term grew larger and larger. The initial handful of scientists at the beginning of the 20th century, used the first definition of fusion, the merging of two atomic nuclei, within the academic subject of physics. The idea was birthed before Albert Einstein's 1905 Nobel Prize winning paper on the photoelectric effect, where the photon energy level was first quantized, boldly stating light is not only a wave, but also a particle. The 1905 paper formed the basis for the discovery of nuclei, which are orbited by electrons. The idea that two nuclei might fuse was in the mind of many scientists. So, they designed experiments, and a student working for a professor asked if he could construct the apparatus and try for fusion. Oliphant was successful with the first "beam-target" fusion. The second fusion was "beam-beam" fusion. The definition of fusion, as a word, was 'simple' in the early 1900's, compared to today's overloaded definitions.
World War II introduced the next definition of fusion, as nuclear fission scientists made the thermonuclear bomb, using fusion as a secondary boost of explosive power. The rush for the Fusion Bomb was on.
Post WWII coined the popular term "Nuke'em with the Bomb." During the Cold War, the original definition was restored for hundreds of scientists, as they set up laboratory experiments to fuse two Elements, in order to empirically determine a particular combination of two isotope's "fusion probability" numerical value. Thus, either, confirming the mathematically modeled probability value, or tweaking the model to match the experimental value. These two value types are now compiled in the software called EMPIRE, available to all scientists, as nuclear science [Quantum Mechanics] has proven to be a tremendous boon to mankind.
In the 1990's, post Cold War, Peace Time, the definition of fusion morphed to it's current meaning, a "commercializable fusion device" able to generate electricity. 'Fusion' is now intellectual property, patentable, making the inventor not only famous, but rich too, via 'Fusion' meaning 'Fusion Power.'
No where is the definition of the word fusion more overloaded than demonstrated on this laundry list web page
There is the Fusion electric car, Fusion CPU chip, Fusion Cookware, Fusion Music, Fusion Dancing, ..., dozens of uses of the word fusion, even Fusionism, a political idea.
The word fusion is popular, like the words quantum and virtual, where these very technical jargon terms of the hard science of physics, have been adopted by people in all lines of endeavor, always changing their definition from that of physics. These words are used by housewives, teenagers, homeless, poor and rich, with dozens of different definitions. Quantum means 'smallest amount,' so a "quantum leap" is not even the distance a baby crawls with the first hand forward. Virtual means almost existing, so a "virtual abundance" means nothing in hand, maybe in the future. Fusion means Power, which is a virtual quantum leap forward for mankind. So far. :-(
The morphing definition of fusion blurs the differences between Fusion Devices.
The lay person reads in the newspapers about Fusion, seeing only one Fusion Device, when there are dozens. Fusion is popularly understood to be Deuterium fusion. The statement, "Fusion uses Deuterium," created a common belief the only Fusion Fuel is Deuterium. By association, the common belief is
There is only one Fusion Device type, which uses the only Fusion Fuel.
The tokamak is the only Fusion Device, such is the common belief in the general population, as popularized by newspapers.
In 2020, when you hear the word "fusion" by the newspaper industry, in mainstream physics, or as a kitchen household term, it's understood the definition is "Fusion Power." Many conversations focus on how the time frame is always "ten years away." Post doc graduates have spent their entire career doing fusion [power], and retired, and passed on.
In the early 21th century, the term Fusion [Power] is fraught with 40 years of repetitive disappointments. There are many types of Fusion [Power]. Cold Fusion and Bubble Fusion are two virtual examples. Even the mainstream efforts of tokamak magnetic confinement and laser inertial confinement have found the very act of creating of their form of plasma to fuse, results in a non sustainable fusion. Break even is close. Ten years away.
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Fortunately, in the last five years, or so, other Fusion Devices have been invented, and gotten consistent yearly funding. Some devices are closing in on the mainstream leaders, and perhaps even passed them, in terms of amount of generated power, getting close to a Beta of 1. Or achieved it, like the Fusor. Beta means efficiency factor. A Beta value of 1 is break even, as much energy comes out as goes in to maintain fusion. Beta of 1 has no extractable, usable energy. It is similar to a perpetual motion machine. Nice to look at. Beta of 1 is not going to be Fusion Power, clean energy for mankind.
The Fusor has over 80 built. One scientist tried to extract energy from the Fusor. They got the energy amount of the flapping of a fly's wings. Tweaking the device to get more extinguished the fusion.
The white elephant of "Beta of 1" does not include the energy to start the device. Energy is used to create the plasma is often not counted by those involved. Beta of 1 means the "run time" efficiency is such the Fusion continues on it's own to stay ignited, constant burning. As such, break even, Beta of 1, is claimed to be a type of the turning point for using Fusion for Power for mankind. Beta of 1 is seen as a key milestone, whose assumption is going beyond Beta of 1 is possible, so funding for Fusion Power continues. A good thing.
Fusion is behind schedule, but has been achieved. For the Tokamak, perhaps soon. Most likely in more than a few more reactor designs, too. Fusion Power currently does exist and on an industrial level, just not advertised, nor marketed.
There is no dedicated communication mechanism to transport early scientific discoveries that are confirmed as accurate to the general public. It is how "science" has always be communicated to the public, with great delays spanning decades. If you read the specialized trade journals, you get science news within 6 months of it happening. Main stream scientific belief takes 5 to 10 years to reach the majority of college professors. Reading popular science magazines you get science news 2 to 5 years after it has become part of 'main stream' scientific belief. Even 10 to 20 years is common in sub specialty fields. Special Interest Groups have highly influenced what the general public reads and hears for the last 200 plus years. That is neither good, nor bad.
Fusion [Power] time frame is soon. Thus, continues the noble fusion research of clean, abundant power for mankind.