North Korea has claimed significant advances in testing a thermonuclear bomb. But how is it different to an atomic bomb? DW takes a look at the fundamental differences between two of history's most destructive weapons.
Developed by the US, the first thermonuclear bomb was fired on Elugelab Island in 1952. It left a massive underwater crater where the island had once been.Image: picture-alliance/dpa/US Department of Energy
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North Korea announced on Sunday that it had conducted a nuclear test using an advanced hydrogen bomb, also known as a thermonuclear bomb, marking departure from its experiments with first generation atomic weapons. But what's the difference between an atomic bomb and the more advanced hydrogen bomb?
The fundamental difference between a hydrogen bomb and atomic bomb is in the detonation process. For an atomic bomb, such as the ones dropped on Nagasaki and Hiroshima, its explosive power is a result of the sudden release of energy upon splitting the nuclei of a heavy element, such as plutonium. This process is known as fission.
Years after the first atomic bomb was developed in New Mexico, the US developed a weapon that relied on the technology of the atomic bomb, but expanded the detonation process to create a stronger explosion. That weapon is called a thermonuclear bomb.
For a thermonuclear bomb, the detonation process comprises several parts, beginning with the detonation of an atomic bomb. The first explosion creates temperatures of millions of degrees, providing enough energy to force the two light nuclei close enough to combine in a second stage known as fusion.
Shape
According to experts, North Korea's latest bomb showed a marked difference from previous ones, displaying a chambered device that suggests a two-stage hydrogen bomb.
"The pictures show a more complete form of a possible hydrogen bomb, with a primary fission bomb and a secondary fusion stage connected together in an hourglass shape," said Lee Choon-geun, senior research fellow at the state-run Science and Technology Policy Institute in South Korea.
Power
The yield of a thermonuclear bomb can be hundreds to thousands of times more powerful than the atomic bomb.
The explosive power of an atomic bomb is often measured in kilotons, or one thousand tons of TNT, while thermonuclear bombs are generally measured in megatons, or one million tons of TNT.
Faces of the Korean War
Uprooted and dislodged - the lives of millions of people were marked by the Korean War. Families were torn apart. To date, it remains unclear how many people were killed in the fighting.
Image: STR/AFP/Getty Images
Abandoned in the rubble
The armistice agreement on July 27, 1953 marked the end of almost three years of war. In September 1950, all alone, this girl cries desperately in the ruins of Incheon. The child's identity is unknown. Shortly before this picture was taken, American troops had retaken the South Korean city from North Korean troops. At this stage of the conflict it all pointed to a South Korean victory.
Image: STR/AFP/Getty Images
Caught between the lines
This family's hut is located in the border area between the warring North and South. By the summer of 1951, the conflict had become static, taking place mainly along the 38th parallel.
Image: Claude de Chabalier/AFP/Getty Images
A constant flow of refugees
These North Korean refugees try to escape the fierce battles that have been raging on since 1951. On their way south they pass by frozen rice fields.
Image: AFP/Getty Images
Heading south
A Korean civilian carries his father on his back as they cross the Han River in 1951. Despite the counter offensive launched by UN forces to stop the Chinese and North Korean troops, Korean civilians continued to flee the northern Korean region.
Image: AFP/Getty Images
Uprooted
A total of 4.5 million North Koreans left their homes because of the war and headed south or abroad. Its unclear how many people lost their lives during the three-year conflict. By the time the armistice agreement was signed in 1953, North Korea had lost half of its pre-war population.
Image: Claude de Chabalier/AFP/Getty Images
Left in ruins
Carrying her wounded grandchild on her back, this elderly woman wanders among the debris of their wrecked home in the aftermath of an air raid by US planes over Pyongyang, the Communist capital of North Korea, in the fall of 1950.
Image: Keystone/Getty Images
Foreign rescuers
A fateful encounter: In the cold of winter, US lieutenant William Doernbach comes across this Korean orphan girl in a deserted village and leaves her in the care of an orphanage. She escapes the orphanage and finds her rescuer. They reunite in May 1951.
