Solar wind controls the magnetosphere-ionosphere coupled system. Most major changes in the EXB drift that occur during storm time can be traced back to the solar wind. Even during quiet times, sudden changes in the IMF Bz component can influence the EXB drift. See the attached paper for details.

What is responsible for the changes in the daytime and nightime phenomenon of the EXB drift?

To answer this question it is first necessary to characterize/explain the kind of changes observed in the daytime and night time EXB drifts.

It is a normal phenomenon, occurring in the ionosphere and is caused by the reversal of the electric field (from eastward during day time to westward). Neutral winds in the thermosphere play a significant role in this.

The above would be modulated to different extent by solar processes and the associated magnetospheric response.

This phenomenon is characteristic of equatorial ionosphere and is caused by the equatorial electric fields which are eastward during the day and has an upward vertical drift and are westward during the night and has downward vertical drift on the ionosphere. this phenomenon is either suppressed or enhanced during storms depending on whether the IMF Bz turns northward (suppress the drift) or southward(enhance the drift). As stated by Moorthy there are other drivers of this phenomenon such as Neutral winds, gravity waves.

Dr. Olwendo's answer is interesting, and I wish he could indicate a recent publication supporting his claims.

Are these changes of EXB drifts currently observed in the equatorial ionosphere at the dawn and dusk terminator, related in some way to the equatorial electrojet?

Lemaire: Yes these changes are related to the equatorial electrojet; But then my understanding of the question was on what then causes the variations in the ExB drift? I have some observations to proof that these variations in ExB (and EEJ) are caused by convective electric fields arising from geomagnetic storms. kindly send me your email so that we can discuss these further particularly in regard to some work am working on at the moment about ExB drift duirng storms around East Africa region which is a low latitude

OK. I would be interested in reading your publication on this issue.

Please send it directly to [email protected].

Attached is a copy of the abstract that I submitted to the last IRI workshop, but that I could not attend, unfortunately.

Also attached is the poster presentation that I presented at the EGU2013 last spring. I am preparing the paper.

Related to disturbance time E X B drift, plasma bubble and EIA some reprints are attached.

One more file attached

Solar eclipses DO NOT occur durin the night time. The solar eclipse 0bscure a portion of the solar radiation reaching the ionosphere and cause the reduction of ionisation by various amount depending on the magnitude of the eclipse.the tome of the day ,latitude of the station any many other parameters which cannot be cescrbed in a small not .He should first study the publlished papers. Solar eclipse do not change the electric field {ExB field}

R. G. Rastogi (Prof.) please can you send me any material to back your argument sir. What i understand about the plasma vertical drift phenomena is the enhancement during the daytime, around 0900-1030 LT hr and the evening time reversal enhancement around 1800-2000 LT hr. Although, solar eclipse obscure a portion of the solar radiation reaching the ionosphere and subsequently reduces the ionization density somewhere later at the F2 region. however, i want to know what really happen if the EXB drift phenomena changes on the solar eclipse day (i.e. there is shift in speculated time for plasma buildup and nighttime resudence).

In addition, i want you to send me any material that i can use in analysis of ionospheric F2 effects during the said events and the site i can download the data and method of analysis.

Solar eclipse is mainly a daytime phenomenon. It could be partial or total. The behaviour of the ionosphere, especially during the later has been investigated by very few researchers. During solar eclipse, radiation that could ionize the dense neutral particle in the thermosphere is either partly or wholly blocked. Considering the continuity equation, electron density is a function of the balance between the production and loss processes as well as the transport process. Therefore, when there is no radiation influx for ionization, the transport process, which is mainly governed by the ExB drift, becomes the dominant process. An evidence of this is reported in the work of Adeniyi et al. (2007) "Signature of the 29 March 2006 eclipse on the ionosphere over an equatorial station - JGR vol. 112, A06314", where only the F2-layer frequency trace was observable on the ionogram during obscuration. Your observed changes in the pattern of the ExB cannot be controlled by solar eclipse because eclipse neither modify the electric field in the thermospheric region nor the Earth's magnetic field. The observed changes may be as a result of other simultaneous Sun-Earth coupling processes.

Dr. Stephen, recently I discovered that the pattern of the ExB drift cannot be controlled by solar eclipse due to some reason you had mentioned. Although, solar eclipse represent a short nighttime during the daytime period, but the accompanying effect are not similar to that the nighttime. The eclipse can only affect the production of electron density and the altitude at which it occurs. During the obscuration the plasma temperature reduced, which responds very quickly along the magnetic field lines to the variation of the energy available from the trapped photoelectrons while the plasma density variation are controlled by more complex and slower transport processes. However, it is very difficult to separate the influence of magnetic storm from solar eclipse. Therefore, the observed changes, if observe, can be traced down to the coupling of the Sun-Earth relationship. Thanking you for relevant answer and eye opening.