What is helicon antenna?
What is helicon antenna?
The difference between a helicon plasma source and an inductively coupled plasma (ICP) is the presence of a magnetic field directed along the axis of the antenna. The presence of this magnetic field creates a helicon mode of operation with higher ionization efficiency and greater electron density than a typical ICP.
What field is helicon used in?
Helicon waves are waves in low-temperature, partially ionized plasmas in a dc magnetic field (B-field). The study of helicons involves both ion–neutral collisions and Larmor orbits, even when the B-field is uniform.
How does a helicon antenna work?
High-density plasma is produced by the use of a helical radio frequency antenna to ionise neutral gas (e.g. argon, krypton, xenon, helium or hydrogen) in a tube closed at one end. The helical antenna excites the gas to dissociate electrons and generate highly energetic ions.
What is a helicon source?
Helicon plasma source is known as efficient generator of uniform and high density plasma. A helicon plasma source was developed for investigation of plasma neutralization and plasma lens in the Institute of Modern Physics in China.
What does Helican mean?
: a large circular tuba similar to a sousaphone but lacking an adjustable bell.
What is Helicon Plasma Thruster?
The Helicon Plasma Thrusters (HPT) are electric in Space propulsion devices based on radiofrequency plasma generation. The resulting plasma is afterwards accelerated by means of a magnetic nozzle to produce thrust.
How do plasma thrusters work?
The thruster works by creating high-current electric arc between the two electrodes. The current running through the cathode back to the power supply induces a magnetic field. The magnetic field and the electric current interact to create a Lorentz force that propels the plasma out of the thruster, producing thrust.
What is Helicon plasma Thruster?
What are halcyon days?
Halcyon Days, which have come to mean any time of happiness and contentment, are actually the 14 days around the winter solstice. According to Greek legend, the halcyon, or kingfisher, built its floating nest around the 14th of December, during which time the gods calmed the seas for the nesting and hatching time.
Who was Helikon?
HELIKON (Helicon) was a mountain-god of Boiotia in central Greece. His peak lay near the Boiotian border with Phokis and was famed for its shrine of the Mousai (Muses).
How does a plasma jet engine work?
Instead of fuel, plasma jet engines use electricity to generate electromagnetic fields. These compress and excite a gas, such as air or argon, into a plasma – a hot, dense ionised state similar to that inside a fusion reactor or star.
Can electricity be used for propulsion?
Electric Propulsion (EP) is a class of space propulsion which makes use of electrical power to accelerate a propellant by different possible electrical and/or magnetic means. The use of electrical power enhances the propulsive performances of the EP thrusters compared with conventional chemical thrusters.
How is the feed line of a helical antenna connected?
The feed line is connected between the bottom of the helix and the ground plane. Helical antennas can operate in one of two principal modes — normal mode or axial mode. In the normal mode or broadside helical antenna, the diameter and the pitch of the aerial are small compared with the wavelength.
How big is the helical antenna compared to the wavelength?
In the normal mode or broadside helical antenna, the diameter and the pitch of the aerial are small compared with the wavelength.
How is impedance matching done in a helical antenna?
Impedance matching (when C=λ) to standard 50 or 75 ohm coaxial cable is often done by a quarter wave stripline section acting as an impedance transformer between the helix and the ground plate. The maximum directive gain is approximately: where N is the number of turns and S is the spacing between turns.
When does the helical antenna operate in axial mode?
When the helix circumference is near the wavelength of operation, the antenna operates in axial mode. This is a nonresonant traveling wave mode, in which instead of standing waves, the waves of current and voltage travel in one direction, up the helix.
