Optimization of Beam Painting for ELF/VLF Wave Generation at HAARP Using Time-of-Arrival Analysis

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Material Information

Title:
Optimization of Beam Painting for ELF/VLF Wave Generation at HAARP Using Time-of-Arrival Analysis
Physical Description:
1 online resource (102 p.)
Language:
english
Creator:
Fujimaru, Shuji
Publisher:
University of Florida
Place of Publication:
Gainesville, Fla.
Publication Date:

Thesis/Dissertation Information

Degree:
Doctorate ( Ph.D.)
Degree Grantor:
University of Florida
Degree Disciplines:
Electrical and Computer Engineering
Committee Chair:
MOORE,ROBERT C
Committee Co-Chair:
RAKOV,VLADIMIR ALEK SANDROVICH
Committee Members:
YOON,YONG KYU
UMAN,MARTIN A
ROY,SUBRATA

Subjects

Subjects / Keywords:
electromagnetics -- elf -- haarp -- ionosphere -- vlf
Electrical and Computer Engineering -- Dissertations, Academic -- UF
Genre:
Electrical and Computer Engineering thesis, Ph.D.
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

Notes

Abstract:
This dissertation experimentally and theoretically investigates the generation of radio waves in the extremely low frequency (ELF, 3-3000 Hz) and very low frequency (VLF, 3-30 kHz) bands by high frequency (HF, 3-30 MHz) heating of the lower ionosphere. ELF and VLF waves can propagate to large distances around the globe with little attenuation, making them ideally suited for long distance communications and ionospheric remote sensing. These waves may also propagate into near-Earth space, where they can control the population of energetic radiation belt particles. Improving the efficiency of this unconventional mechanism for ELF/VLF wave generation is the primary emphasis of this work. For the experimental observations presented herein, the ELF/VLF signal detected at the receiver is considered to be the sum of several multi-path components. These multi-path components are produced by reflections from the ground and the lower ionosphere. A novel time-of-arrival (TOA) analysis technique is applied to observations to distinguish between line-of-sight (LOS) and ionospherically-reflected (IR) components. This decomposition enables the experimental differentiation of HF heating (i.e., source) effects and Earth-ionosphere waveguide (i.e., propagation) effects. TOA analysis of experimental observations for various HF heating schemes are compared against a theoretical model to demonstrate the validity of the technique. TOA analysis is applied to evaluate the ELF/VLF source properties produced by rapidly scanning the HF beam across the ionosphere, a very efficient modulation technique known as beam-painting. By precisely controlling the duration of the HF pulse during the beam-painting experiments, the amplitude and phase of individual ELF/VLF array elements are experimentally measured. The influence of the source area, phasing distribution, heating and cooling time scales, and obliqueness of the HF beam on the received ELF/VLF amplitude are experimentally quantified for the first time. Based on these observations, a simple change to the modulation format is proposed to significantly increase the received ELF/VLF amplitude by >4 dB and the HF-to-ELF conversion efficiency by >7 dB. Lastly, a rigorous optimization method is applied to maximize the received ELF/VLF wave amplitude. The optimization is based on experimental observations, and utilizes the observed amplitudes, phases, and propagation delays associated with 8 different HF heating locations. The optimal heating pattern is predicted to increase the received ELF/VLF amplitude by ~7 dB and the HF-to-ELF conversion efficiency by ~11 dB, constituting a tremendous improvement over the current state-of-the-art modulation formats.
General Note:
In the series University of Florida Digital Collections.
General Note:
Includes vita.
Bibliography:
Includes bibliographical references.
Source of Description:
Description based on online resource; title from PDF title page.
Source of Description:
This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Statement of Responsibility:
by Shuji Fujimaru.
Thesis:
Thesis (Ph.D.)--University of Florida, 2014.
Local:
Adviser: MOORE,ROBERT C.
Local:
Co-adviser: RAKOV,VLADIMIR ALEK SANDROVICH.
Electronic Access:
RESTRICTED TO UF STUDENTS, STAFF, FACULTY, AND ON-CAMPUS USE UNTIL 2014-11-30

Record Information

Source Institution:
UFRGP
Rights Management:
Applicable rights reserved.
Classification:
lcc - LD1780 2014
System ID:
UFE0046495:00001