The determination of the field intensity of a magnetodynamic disturbance in the lower ionosphere from the field intensity measured above the Earth's surface

1967 ◽  
Vol 11 (1) ◽  
pp. 65-79 ◽  
Author(s):  
Josef Bochníček
Keyword(s):  
Field Intensity ◽  
Lower Ionosphere

scholarly journals Cluster observations of ELF/VLF signals generated by modulated heating of the lower ionosphere with the HAARP HF transmitter

2004 ◽  
Vol 22 (7) ◽  
pp. 2643-2653 ◽  
Author(s):  
M. Platino ◽  
U. S. Inan ◽  
T. F. Bell ◽  
J. Pickett ◽  
E. J. Kennedy ◽  
...  
Keyword(s):  
High Frequency ◽  
Lower Ionosphere ◽  
Spectral Signature ◽  
Closed Field ◽  
Ionospheric Heating ◽  
Higher Power ◽  
Power Operation ◽  
Field Lines ◽  
Vlf Waves

Abstract. It is now well known that amplitude modulated HF transmissions into the ionosphere can be used to generate ELF/VLF signals using the so-called "electrojet antenna". Although most observations of the generated ELF/VLF signals have been made on the ground, several low and high-altitude satellite observations have also been reported (James et al., 1990). One of the important unknowns in the physics of ELF/VLF wave generation by ionospheric heating is the volume of the magnetosphere illuminated by the ELF/VLF waves. In an attempt to investigate this question further, ground-satellite conjunction experiments have recently been conducted using the four Cluster satellites and the HF heater of the High-Frequency Active Auroral Research Program (HAARP) facility in Gakona, Alaska. Being located on largely closed field lines at L≈4.9, HAARP is currently also being used for ground-to-ground type of ELF/VLF wave-injection experiments, and will be increasingly used for this purpose as it is now being upgraded for higher power operation. In this paper, we describe the HAARP installation and present recent results of the HAARP-Cluster experiments. We give an overview of the detected ELF/VLF signals at Cluster, and a possible explanation of the spectral signature detected, as well as the determination of the location of the point of injection of the HAARP ELF/VLF signals into the magnetosphere using ray tracing.

scholarly journals Determination of magnetic field intensity on open sample

2021 ◽  
Vol 72 (6) ◽  
pp. 419-422
Author(s):  
Karol Hilko ◽  
Vladimír Jančárik ◽  
Filip Kafka
Keyword(s):  
Magnetic Field ◽  
Numerical Simulation ◽  
Field Intensity ◽  
Magnetic Field Intensity ◽  
Sample Surface ◽  
Steel Sample ◽  
Sufficient Accuracy ◽  
The Magnetic Field

Abstract The work is focused on the refinement of the determination of the magnetic field intensity in a Charpy-shaped steel sample. When measuring on an open sample, the intensity of the magnetic field cannot be determined directly from the current by the magnetizing winding. The distribution of the magnetic field around the sample was determined by numerical simulation, the dependence of its intensity on the distance from the sample surface is fitted with sufficient accuracy by a polynomial of the 3rd degree. A system of sensors sensing the distribution of the field at selected points above the sample was designed; by extrapolation using said fitting function, the intensity of the magnetic field on the surface of the examined sample is determined.

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