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Chapter 080 Magnetic Storm

But Clark was the first to illustrate the role of geostationary orbits for broadcast and relay communications satellites.

Therefore, the geostationary orbit is sometimes also called the Clark orbit.

Correspondingly, there is an area 35km above sea level called the Clark Belt, which is located in the equatorial plane and can be used as a quasi-stationary orbit.

In addition, the circumference of Clark's orbit is approximately 265km.

A satellite or artificial satellite that orbits the Earth in this orbit is always at the same location on the Earth's surface.

Its orbital eccentricity and orbital inclination are both zero. The movement period is 23 hours, 56 minutes and 04 seconds, which is consistent with the earth's rotation period, and the orbit radius is 42164.169km.

Since the subsatellite trajectory of a satellite moving in a geostationary orbit is a point, observers on the surface can always observe the satellite at the same position in the sky at any time, and will find that the satellite is stationary in the sky. Therefore, many Artificial satellites, especially communication satellites, mostly use geostationary orbit.

Generally, the geostationary orbit is a highly dense area of ​​communication satellites. It is located in the near-equatorial area about 6.6 Earth radii from the center of the earth.

The space environment in this area is mainly composed of high-energy particles other than the gravitational field, thermal plasma, plasma layer plasma, ring current, magnetic field, solar electromagnetic radiation, meteoroids and space debris.

The geostationary orbit area is an area where the earth's space environment is seriously affected by solar activity. When strong solar wind arrives, the magnetosphere will be compressed, and the geostationary orbit area is completely exposed to solar cosmic rays and high-speed solar wind.

During magnetic storms or substorms, high-temperature plasma injected from the magnetotail can also reach this area, making this area a high-risk area for space environment-induced spacecraft anomalies, in which high-energy particle (including solar proton events) environment and substorm injection The thermal plasma environment is the most important environment causing anomalies and is the area with the most serious spacecraft charging problems.

Joule was a famous British experimental physicist.

He was born in the suburbs of Manchester, England in 1818. He was the son of a wealthy brewery owner.

He was taught by tutors at home since he was a child. At the age of 16, he and his brother studied with the famous chemist Dalton. This played a key guiding role in Joule's life and made him have a strong interest in science. Later, he He started various experiments at home and became an amateur scientist.

At this time, the phenomenon of electromagnetic force and electromagnetic induction had just been discovered, and the electric motor—called a magneto at the time—had just appeared. People did not yet fully understand the inherent laws of electromagnetic phenomena, and they lacked a deep understanding of circuits.

I just felt that the magneto was very novel and could potentially replace the steam engine as a new power source with higher efficiency and easier management, so an electrical craze swept across Europe and even the United States.

Joule was just 20 years old at the time, at a sensitive age, and had good experimental conditions at home (his father probably had a steam engine in his factory). He was very interested in innovating power equipment, so he got involved in the electrical boom and began to study magnets. The motor comes.

In the years from 1838 to 1842, Joule wrote a total of eight communications and papers on electric machines, one on batteries, and three on electromagnets.

He noticed the heating phenomenon in the motor and circuit through various experiments on the magneto. He believed that this, like the friction phenomenon in the operation of the machine parts, was the source of power loss.

So he began to study the thermal effects of electric current.

In 1841, he published an article "Heat generated by metallic conductors of electricity and heat in batteries during electrolysis" in the "Philosophical Magazine", describing his experiment: In order to determine the thermal power of a metal wire, let the wire pass through a piece of glass tube, and then tightly wrap it around the tube, leaving a gap between each turn and the coil ends separated. Then put the glass tube into a container of water, and use a thermometer to measure the temperature change produced by the water after electricity is turned on.

During the experiment, he first used wires of different sizes, and then changed the intensity of the current. The result was that "the heat generated by the voltaic current passing through the metal conductor within a certain period of time is proportional to the product of the square of the current intensity and the resistance of the conductor."

This is the famous Joule's law, also known as iR's law.

Subsequently, he conducted a large number of experiments with electrolytes, proving that the above conclusion was still correct.

The discovery of iR's law gave Joule a clear understanding of the role of current in circuits.

He imitated the blood circulation in the animal body, compared the battery to the heart and lungs, and compared the current to the blood. He pointed out: "Electricity can be regarded as an important medium for carrying, distributing and transforming chemical heat", and believed that in the battery " Burning a certain amount of chemical "fuel" will emit a corresponding amount of heat in the circuit (including the battery itself), which should be the same as the direct combustion of these fuels in oxygen.

Please note that Joule had already used the term "conversion of chemical heat" at this time, indicating that he had established a universal concept of energy conversion and had a clear understanding of the equivalence of heat, chemical action and electricity.

However, the strongest evidence for this equivalence is direct experimental data on thermal work equivalents.

It was the exploration of heat loss in magnetos that prompted Joule to conduct a large number of thermal work equivalent experiments.

In 1843, Joule described his purpose in the article "Thermal Effect of Magnetoelectricity and the Mechanical Value of Heat", writing:

“I believe it to be a given that the electricity from the magneto has the same thermal properties throughout the circuit as the current produced by other sources.

Of course, if we consider that heat is not a substance, but a state of vibration, there seems no reason why it cannot be caused by the action of a simple mechanical property, such as that of a coil rotating between the poles of a permanent magnet.

At the same time, it must also be admitted that no experiments have so far been able to reach a verdict on this very interesting question, because all these experiments have been limited to local parts of the circuit, which leaves questions.

Is the heat generated or transferred from the coil inducing the magnetic current?

If heat is transferred out of the coil, the coil itself will become colder.

…So, I decided to work on clearing up the uncertainty about magnetoelectric heating. "

Joule placed the magneto in a bucket as a calorimeter, rotated the magneto, and led the current from the coil to the galvanometer for measurement, and at the same time measured the change in water temperature in the bucket.

Experiments have shown that the heat generated by a magneto coil is also proportional to the square of the current.

Joule then connected the magneto as a load to the circuit, and connected another battery to the circuit to observe the generation of heat inside the magneto. At this time, the magneto was still placed in the bucket as a calorimeter. Joule continued to write: "I By turning the wheel to one side, the magneto can be connected to the current in the opposite direction, and by turning the wheel to the other side, the magneto can be used to increase the current. In the former case, the instrument has all the characteristics of the magneto, but in the latter case it is counterproductive, and it consumes the machinery. force."

......

To be continued

Chapter 081 Preview of the Legion Commander