Sunday, September 3, 2017

North Korea's Threat with a Hydrogen Bomb - How Destructive are They? & What are They?

What is a hydrogen bomb? A look at the latest potential threat from North Korea

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North Korea's announcement on Sunday that it has successfully tested a hydrogen bomb meant to be loaded onto an intercontinental ballistic missile has raised alarm bells across the world, in part because of the weapon's destructive power.
Here's a look at what a hydrogen bomb is, and what exactly it can do:

Stronger than the atomic bombs used during WWII

Los Alamos National Laboratory (LANL), a federally funded research and development center focused on national security issues, suggests that thermonuclear weapons, including so-called hydrogen bombs, are more powerful than atomic weapons, like the ones the United States used on Japan during World War II, killing hundreds of thousands of people.
 Atomic bombs produce energy through "fission, or the splitting of heavy nuclei into smaller units, releasing energy," according to LANL.
Thermonuclear weapons use a fission bomb to start "a fusion reaction where light nuclei, with few protons and neutrons, join together and release energy," according to LANL. This represents the same reaction that powers stars, LANL notes.
When a newsreader for North Korean state-run television announced today's test, she called it a "complete success," adding that the "two-stage thermonuclear weapon" had "unprecedented" strength.

Mankind tested hydrogen bombs, but not used them in war

 The U.S. first ran a test of its own hydrogen bomb at Eniwetok in the Marshall Islands on November 1, 1952, during a mission called Operation Ivy.

"The Atomic Energy Commission announced tonight ‘satisfactory’ experiments in hydrogen weapon research … In a three-paragraph announcement, the Commission did not go so far as to state that a full-scale hydrogen bomb had been detonated, but it did say ‘experiments contributing’ to hydrogen bomb research had been completed,” the New York Times reported at the time.
Footage of the test shows the haunting and familiar "mushroom cloud" of smoke billowing outward into the sky in repeated waves.
The test represented the next stage in development for weaponry, and an escalation in potential damage: Nuclearweaponarchive.org, a website that tracks the history of atomic explosions, suggests that a blast created during Operation Ivy was "considerably more powerful than all the high explosives used in two World Wars put together."
A summary produced by The History Channel suggests that the blast is "approximately 1,000 times more powerful than conventional nuclear devices" like the atomic bomb.
Responding to the threat posed by the U.S., the U.S.S.R. tested "Joe 4," a thermonuclear device, in August of 1953.

What is a Hydrogen Bomb?

Hydrogen bomb or H-bomb, weapon deriving a large portion of its energy from the nuclear fusion of hydrogen isotopes. In an atomic bomb, uranium or plutonium is split into lighter elements that together weigh less than the original atoms, the remainder of the mass appearing as energy. Unlike this fission bomb, the hydrogen bomb functions by the fusion, or joining together, of lighter elements into heavier elements. The end product again weighs less than its components, the difference once more appearing as energy. Because extremely high temperatures are required in order to initiate fusion reactions, the hydrogen bomb is also known as a thermonuclear bomb.

The first thermonuclear bomb was exploded in 1952 at Enewetak by the United States, the second in 1953 by Russia (then the USSR). Great Britain, France, and China have also exploded thermonuclear bombs, and these five nations comprise the so-called nuclear club—nations that have the capability to produce nuclear weapons and admit to maintaining an inventory of them. The three smaller Soviet successor states that inherited nuclear arsenals (Ukraine, Kazakhstan, and Belarus) relinquished all nuclear warheads, which have been removed to Russia. Several other nations either have tested thermonuclear devices or claim to have the capability to produce them, but officially state that they do not maintain a stockpile of such weapons; among these are India, Israel, and Pakistan. South Africa's apartheid regime built six nuclear bombs but dismantled them later.

The presumable structure of a thermonuclear bomb is as follows: at its center is an atomic bomb; surrounding it is a layer of lithium deuteride (a compound of lithium and deuterium, the isotope of hydrogen with mass number 2); around it is a tamper, a thick outer layer, frequently of fissionable material, that holds the contents together in order to obtain a larger explosion. Neutrons from the atomic explosion cause the lithium to fission into helium, tritium (the isotope of hydrogen with mass number 3), and energy. The atomic explosion also supplies the temperatures needed for the subsequent fusion of deuterium with tritium, and of tritium with tritium (50,000,000°C and 400,000,000°C, respectively). Enough neutrons are produced in the fusion reactions to produce further fission in the core and to initiate fission in the tamper.

Since the fusion reaction produces mostly neutrons and very little that is radioactive, the concept of a "clean" bomb has resulted: one having a small atomic trigger, a less fissionable tamper, and therefore less radioactive fallout. Carrying this progression further results in the neutron bomb, which has a minimum trigger and a nonfissionable tamper; it produces blast effects and a hail of lethal neutrons but almost no radioactive fallout and little long-term contamination. This theoretically would cause minimal physical damage to buildings and equipment but kill most living things. Developed in 1958 by the United States and successfully tested, a number of countries are believed to have included such weapons in their nuclear arsenals; the United States built several hundred neutron bombs in the 1980s but did not deploy them.

The theorized cobalt bomb is, on the contrary, a radioactively "dirty" bomb having a cobalt tamper. Instead of generating additional explosive force from fission of the uranium, the cobalt is transmuted into cobalt-60, which has a half-life of 5.26 years and produces energetic (and thus penetrating) gamma rays. The half-life of Co-60 is just long enough so that airborne particles will settle and coat the earth's surface before significant decay has occurred, thus making it impractical to hide in shelters. This prompted physicist Leo Szilard to call it a "doomsday device" since it was capable of wiping out life on earth.

Like other types of nuclear explosion, the explosion of a hydrogen bomb creates an extremely hot zone near its center. In this zone, because of the high temperature, nearly all of the matter present is vaporized to form a gas at extremely high pressure. A sudden overpressure, i.e., a pressure far in excess of atmospheric pressure, propagates away from the center of the explosion as a shock wave, decreasing in strength as it travels. It is this wave, containing most of the energy released, that is responsible for the major part of the destructive mechanical effects of a nuclear explosion. The details of shock wave propagation and its effects vary depending on whether the burst is in the air, underwater, or underground.

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