At that moment, nuclear fusion finally came true. In order to create energy comparable to stars on Earth, scientists have been studying nuclear fusion technology for many years. Recently, a US scientific team has successfully realized "burning plasma" through high-power laser light which saw the energy produced by the nuclear fusion exceed total input energy.
Nuclear fusion mainly simulates the reactions of solar energy. The core of the sun is approximately 27 million degrees Celsius, fuses approximately 620 million tons of hydrogen into 616 million tons of helium every second, and converts 4 million tons of matter into energy. Creating these reactions on Earth requires a lot of energy to start the process.
This achievement took place at the Lawrence Livermore National Laboratory's (LLNL) National Ignition Facility (NIF), which has been in operation since 2009, and is where scientists study nuclear fusion technology. Enormous pressures and temperatures are generated with 192 lasers emitting 1.9 megajoules (MJ) of ultraviolet energy and then shined into a hohlraum as small as a ball bearing, imploding the fuel capsule inside to have an opportunity to fuse atoms into helium, and release a huge amount of energy.
This time, the nuclear fusion reaction at the NIF successfully released 1.35 MJ of energy, the first time the fusion process produced more energy than total input energy.
LLNL physicist Alex Zylstra stated, fusion experiments have used numerous "external" heating systems over the past few decades to drive fusion reactions at high temperatures and pressures but now the community has reached a new milestone, allowing fusion reactions to heat themselves for the first time. According to the team, this is the so-called self-heating effect. Nuclear fusion plasma can heat itself when self-supplied energy is greater than external energy and enters the state of burning plasma.
Now scientists have taken a small but crucial step at the NIF. In this experiment, scientists first fine-tuned the device, including expanding the laser energy focused on the fuel, while changing the geometry of the target and the way energy is transferred between the laser beams in a completely new way to control the internal compression and heating of the fuel explosion process, creating self-heating plasma.
LLNL physicist and lead author Annie Kritchey stated that a burning plasma state has been reached for the first time at a nuclear fusion research facility. Even though the plasma only lasted for a short nanosecond and it will take decades to achieve a sustained and stable nuclear fusion reaction, the team has finally taken an important step towards ignition and still believes that this fleeting self-heating plasma is an important proof of concept.
（Image：Lawrence Livermore National Laboratory, CC BY-SA 3.0, via Wikimedia Commons）
