Neutral winds

Lane A. L. and Domingue D. L. (1997) lUE s view of Callisto detection of an SO2 absorption correlated to possible toms neutral wind alterations. Geophys. Res. Lett. 24, 1143-1146. 

Dynamo electric field Electric field created in the E and F regions by plasma that is dragged along with the neutral wind across magnetic field lines. 

At mid- and low-latitudes, the ionospheric plasma is strongly affected by the motion of the earth s upper atmosphere (neutral wind). In general, this neutral wind blows away from the subsolar point on the dayside and around to the nightside. The ionospheric plasma at midlatitudes is confined to move along magnetic field lines therefore the meridional wind exerts a major influence on the ionosphere. On the dayside, this wind blows toward the poles, and the ionization is driven downward. On the nightside, the meridional wind blows toward the equator, and the ionization is driven up field lines. 

At low latitudes, the geomagnetic field lines are nearly horizontal, which introduces some unique transport effects. First, the meridional neutral wind can very effectively induce an interhemispheric flow of plasma along geomagnetic field lines. At solstice, the dayside wind blows across the equator from the summer to the winter hemisphere. As the ionospheric plasma rises on the summer side of the equator, it expands and cools, while on the winter side it is compressed and heated as it descends. 

Another interesting transport effect at low latitudes is the so-called equatorial fountain. In the daytime equatorial ionosphere, eastward electric fields associated with neutral wind-induced ionospheric currents drive a plasma motion that is upward. The plasma lifted in this way then diffuses down the magnetic field lines and away from the equator due to the action of gravity. This combination of electromagnetic drift and diffusion produces a fountainlike pattern of plasma motion. 

An approximate comparison between the number of conventional (HE) and chemical rockets launched from multi-barrel launchers to achieve a level of casualties of about 50-60 per cent, using 6 multi-barrel rocket launchers, with observed fire in neutral wind speed conditions of 3 metres per second. 

FIGURE 10.156 Improved ferroresonant transformer design incorporating a compensating winding and a neutralizing winding. 

Neutralizing winding (W ), which cancels out most of the harmonic content of the output voltage. Without some form of harmonic reduction, the basic ferroresonant transformer would be... 

Abstract. We have obtained hi d c Lition spectra of the CO band-head emission from five young stars. We find a variety of line shapes, and we compare the profiles with those predicted by models of accretion disks and neutral winds. Standard accretion disks are able to reproduce the fluxes, profiles, and optical d ths of our sources, with accretion rates of 10 Mq yr. Winds successfully account for the fluxes and profiles provided the wind does not cool adiabatically, but remains hot at least out to where the density is too low to excite CO emission. However, our wind modd predicts optically-thin emission, which is inconsistent with low-resdhition data. We therefore prefer disks as the origin of the CO band-head emission in young stars. 

The frame below contains spectra of Serpois SYS 20, a low luminosity, dose (1.5 arcsec) binary star with the unusual property that the two components have very similar spectral energy distributions (SED s), yet the southern object is approximately four times as luminous. We rotated the instrument mount to place the slit along the line joining the two stars, then took two 60 second K spectra. As expected from the SED s, the spectra have a similar shape, but note the presence of Bry and CO Av = 2 emission in the northern (filter) source. The CO emission may arise in a warm, neutral wind or an accretion disk (Carr 1989, Ap.J. 345, 522), both interesting possibilities given the proximity (400 AU) of the brighter companion. 

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