APPLICATION OF THE FAST CYCLOTRON WAVE OF A MAGNETICALLY FOCUSED ELECTRON BEAM TO FREQUENCY MULTIPLICATION

Journal Article · Sun Apr 01 04:00:00 EST 1962 · Dissertation Abstr.

OSTI ID:4829284

Davis, D T

Transverse excitation of a magnetically focused electron beam produces transverse velocity raodulation components which propagate along the electron beara in two fundamental modes called the fast and the slow cyclotron waves. The phase velocities of propagation for these waves are given by u/sub 1,2/ = STAu/ sub 0/1 plus or minus ( omega /sub c/ omega )!, where u/sub 0/ is the axial velocity of the electron beam, omega is the angular electron cyclotron frequency, and omega is the angular frequency of the excitation. If omega = omega c, the phase velocity of the fast wave becomes infinite, and electrons all along the beam rotate in phase with the modulating field. Electrons initially in an accelerating field will remain in an accelerating field, increasing their kinetic energies and radii of rotation, while those in a decelerating field will give up energy and decrease their radii of rotation, eventually moving to the axis of rotation near the center of the beam from which they can be moved only by an accelerating field. Thus the electron beam will leave the region of transverse excitation rotating about its original axis with the kinetic energy of rotation representing the energy delivered to the beam by the high frequency field. If this rotating beam is passed through a magnetron-type resonator having 2k cavities tuned to the kth harmonic of the cyclotron frequency, the beam can induce a harmonic current in the resonator and can move continuously in a retarding phase of the resulting electric field, since it will pass one resonator during every half cycle of the harmonic frequency. Under these conditions, the rotational kinetic energy of the electron beam can be converted into r-f energy at the harmonic, and thus the device will act as a frequency multiplier. A multiplier of this type was investigated. A third harraonic version produced 28 milliwatts of output power at 29,100 Mc with 9700 Mc excitation of the order of 100 watts. Theoretical analysis indicates that this conversion efficiency should be improved by nearly two orders of magnitide by use of a proper electron gun, and possibilities for generating several hundred milliwatts in the three millimeter wavelength range seem favorable.

• Research Organization: Ohio State Univ., Columbus
• NSA Number: NSA-16-024297
• OSTI ID: 4829284
• Journal Information: Dissertation Abstr., Journal Name: Dissertation Abstr. Vol. Vol: 22
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

CONVERSION
CYCLOTRON FREQUENCY
CYCLOTRON RADIATION
EFFICIENCY
ELECTRIC FIELDS
ELECTRON BEAMS
ELECTRON TUBES
ELECTRONS
FREQUENCY
MAGNETIC FIELDS
MAGNETRONS
MODULATION
MOTION
PHYSICS
ROTATION
VELOCITY