What is Alfven wave in plasma?

Definition. An Alfvén wave in a plasma is a low-frequency (compared to the ion cyclotron frequency) travelling oscillation of the ions and the magnetic field. The motion of the ions and the perturbation of the magnetic field are in the same direction and transverse to the direction of propagation.

What is kinetic Alfven waves?

Kinetic Alfven waves represented by undulation in the magnetic field vector. The waves initially proposed by Alfvén are considered ‘basic’. They have a characteristic that they are compressional, which means that magnetic field variation of the Alfvén waves is in the direction of the wave motion.

What is the plasma universe theory?

role of Alfvén Alfvén devised “plasma cosmology,” a concept that challenged the big-bang model of the origin of the universe. The theory posited that the universe had no beginning (and has no foreseeable end) and that plasma—with its electric and magnetic forces—has done more to organize matter in the universe…

Which of the following theories was proposed by Hannes Alfven?

theory of magnetic storms In 1939, Alfvén proposed the theory of magnetic storms and auroras and the theory of plasma dynamics in the earth’s magnetosphere.

Are Alfvén waves transverse?

A variant is the “kinetic” Alfvén wave which is transverse, with strong magnetic field variation perpendicular to the wave motion, so can trade energy between the different frequencies which might propagate through a plasma.

What is the Alfvén speed?

The Alfvén speed ranges from 5–14 km s−1, mainly 6–11 km s−1. The plasma-β is established to be 0.3–1.6. The density inside the umbral photosphere ranges from (1–10) × 10−4 kg m−3, which gives the number density ~1016–1017 cm−3.

Who discovered Alfven waves?

Hannes Alfvén In 1942 (Alfvén 1942), Hannes Alfvén discovered that if a perfectly conducting medium (e.g., a fully ionized gas; i.e., a plasma) is immersed in a finite background magnetic field \\varvec{B}_0; electromagnetic waves can then propagate within it.

What are the 3 sources of plasma on Earth?

You probably encounter plasma more often than you think. More exotic sources of plasma include particles in nuclear fusion reactors and weapons, but everyday sources include the Sun, lightning, fire, and neon signs. Other examples of plasma include static electricity, plasma balls, St. Elmo’s fire, and the ionosphere.

How plasma is created?

A plasma is created when one or more electrons are torn free from an atom. A plasma is generally a mix of these positively charged ions and negatively charged electrons. Most plasmas are created when extra energy is added to a gas, knocking electrons free from atoms. High temperatures often cause plasmas to form.

Does the human body have plasma?

Plasma is the liquid portion of blood. About 55% of our blood is plasma, and the remaining 45% are red blood cells, white blood cells and platelets that are suspended in the plasma.

Is plasma a wave?

As in any fluid, waves can propagate through a plasma. Because of the electrical character of the plasma medium, plasma waves are very complex. Some of these waves have electric and magnetic fields, and are similar to the electromagnetic waves in free space.

How do you calculate Alfven speed?

The Alfvén velocity calculator helps you compute the velocity of a magnetohydrodynamic wave, a type of a plasma wave. Alfvén velocity calculator

  1. B [T] is the magnetic field,
  2. μ0 = 4 * π * 10^(-7) [T * m / A] is the magnetic permeability of free space,
  3. ρ [kg/m³] is the density of ions,
  4. v [m/s] is the Alfvén velocity.

What are MHD waves?

Magnetohydrodynamic waves are propagating disturbances found in electrically conducting fluids permeated by magnetic fields where magnetic tension provides a restoring force on fluid parcels moving across field lines.

What is Alfven radius?

The Alfvén radius is a distance where the magnetic energy density is equal to the kinetic energy density, or bulk velocity equals the Alfvén velocity. For magnetized planets a concept of Alfvén radius is important as for the interaction with the solar/stellar wind, either for the inter-magnetospheric processes.

What is plasma pressure?

Plasma pressure consists of many parameters; they are plasma density (ne,i), plasma temperature (Te,i), impurity (Zeff), and fast beam ions. Among these parameters, ion density (ni) and fast beam ions can not be measured directly in practice.

What is a reconnection event?

Magnetic reconnection (henceforth called “reconnection”) refers to the breaking and reconnecting of oppositely directed magnetic field lines in a plasma. In the process, magnetic field energy is converted to plasma kinetic and thermal energy. Reconnection is at the heart of many spectacular events in our solar system.

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