Event Title

Experimental Evidence of a Diurnal Character of Horizontal Drift Velocities at F Region Heights

Location

Yosemite National Park

Start Date

2-7-1974 9:00 AM

End Date

2-7-1974 9:15 AM

Description

Three-dimensional drifts were measured during both day and night with the Millstone Hill Incoherent Scatter Radar for two periods of 36 hours during Summer, 1973. These results were averaged with all previously available north-south and east-west velocities to determine whether the drift velocity perpendicular to the magnetic field varies diurnally or semi-diurnally. A Fourier analysis was performed on this average velocity and the diurnal component was found to be the dominant mode. Comparison with predictions of dynamo theories show that the electrostatic field alone cannot account for the observed drift velocities but the "total" electric field (i.e. dynamo field plus electrostatic field) can produce drift velocities substantially in agreement with the measured values. This total electric field combined with a perturbation field of magnetospheric origin can also explain the measured pattern of drift velocity daring geomagnetically disturbed conditions.

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Feb 7th, 9:00 AM Feb 7th, 9:15 AM

Experimental Evidence of a Diurnal Character of Horizontal Drift Velocities at F Region Heights

Yosemite National Park

Three-dimensional drifts were measured during both day and night with the Millstone Hill Incoherent Scatter Radar for two periods of 36 hours during Summer, 1973. These results were averaged with all previously available north-south and east-west velocities to determine whether the drift velocity perpendicular to the magnetic field varies diurnally or semi-diurnally. A Fourier analysis was performed on this average velocity and the diurnal component was found to be the dominant mode. Comparison with predictions of dynamo theories show that the electrostatic field alone cannot account for the observed drift velocities but the "total" electric field (i.e. dynamo field plus electrostatic field) can produce drift velocities substantially in agreement with the measured values. This total electric field combined with a perturbation field of magnetospheric origin can also explain the measured pattern of drift velocity daring geomagnetically disturbed conditions.