Rocket-based measurements of ion velocity, neutral wind, and electric field in the collisional transition region of the auroral ionosphere

2009 ◽  
Vol 114 (A4) ◽  
pp. n/a-n/a ◽  
Author(s):  
L. Sangalli ◽  
D. J. Knudsen ◽  
M. F. Larsen ◽  
T. Zhan ◽  
R. F. Pfaff ◽  
...  
Keyword(s):  
Electric Field ◽  
Transition Region ◽  
Neutral Wind ◽  
Auroral Ionosphere ◽  
Ion Velocity ◽  
Collisional Transition

scholarly journals On the origin of pre-reversal enhancement of the zonal equatorial electric field

2009 ◽  
Vol 27 (5) ◽  
pp. 2053-2056 ◽  
Author(s):  
M. C. Kelley ◽  
R. R. Ilma ◽  
G. Crowley
Keyword(s):  
Electric Field ◽  
Equatorial Electrojet ◽  
Neutral Wind ◽  
Radio Observatory ◽  
Dominant Mechanism ◽  
Partial Closure ◽  
Incoherent Scatter ◽  
Unique Event ◽  
The Earth ◽  
Dusk Sector

Abstract. In November 2004, a large and variable interplanetary electric field (IEF) was felt in the reference frame of the Earth. This electric field penetrated to the magnetic equator and, when the Jicamarca Radio Observatory (JRO) was in the dusk sector, resulted in a reversal of the normal zonal component of the field. In turn, this caused a counter-electrojet (CEJ), a westward current rather than the usual eastward current. At the time of the normal pre-reversal enhancement (PRE) of the eastward field, the Jicamarca incoherent scatter radar (ISR) observed that the westward component became even more westward. Two of the three current explanations for the PRE depend on the neutral wind patterns. However, this unique event was such that the neutral wind-driven dynamos could not have changed. The implication is that the Haerendel-Eccles mechanism, which involves partial closure of the equatorial electrojet (EEJ) after sunset, must be the dominant mechanism for the PRE.

Global distribution of persistence of total electron content anomaly

2020 ◽  
Author(s):  
Yang-Yi Sun ◽  
Chieh-Hong Chen ◽  
Jann-Yenq Liu ◽  
Tsung-Yu Wu
Keyword(s):  
Electric Field ◽  
Total Electron Content ◽  
Electron Content ◽  
Neutral Wind ◽  
Large Area ◽  
Atmospheric Gravity Wave ◽  
Total Electron ◽  
Ionospheric Plasma Density ◽  
Gps Products ◽  
Ionospheric Electric Field

<p>Solar activities can disturb the ionosphere globally and induce ionospheric weather phenomena that transit rapidly through a large area. By contrast, sometimes the ionospheric plasma density can remain high or low over a certain location for a few days, which are difficult to be attributed to solar activities. This study shows the location preference of the positive and negative total electron content (TEC) anomalies persisting continuously longer than 24 hours (cross the two terminators) at middle and low latitudes (within ±60ºN geomagnetic latitudes). The TEC is obtained from the global ionospheric map (GIM) of the Center for Orbit Determination in Europe (CODE) (ftp://cddis.gsfc.nasa.gov/pub/gps/products/ionex) under the geomagnetic quiet condition of Kp ≤ 3o during the period of 2005–2018. There are a few (less than 4%) TEC anomalies that can persist over 24 hours. The persistence of the positive TEC anomaly along the ring of fire on the western edge of the Pacific Ocean. The high persistence of the TEC anomalies at midlatitudes suggests that thermospheric neutral wind contributes to the anomaly formation. The temporal and spatial anomalies of the ionospheric electric field, atmospheric electric field (flash), atmospheric gravity wave, and neutral wind over the ring of fire should be further examined for explaining whether the persistence of the TEC anomalies associates with lithospheric activities.</p>

Studies of theEregion neutral wind in the quiet auroral ionosphere

1994 ◽  
Vol 99 (A5) ◽  
pp. 8801 ◽  
Author(s):  
Asgeir Brekke ◽  
Satonori Nozawa ◽  
Trygve Sparr
Keyword(s):  
Neutral Wind ◽  
Auroral Ionosphere

scholarly journals Bootstrap current and parallel ion velocity in imperfectly optimized stellarators

2020 ◽  
Vol 86 (1) ◽  
Author(s):  
Peter J. Catto ◽  
Per Helander
Keyword(s):  
Magnetic Field ◽  
Kinetic Equation ◽  
Electric Field ◽  
Flow Velocity ◽  
Collision Frequency ◽  
Rotation Frequency ◽  
Radial Electric Field ◽  
Local Form ◽  
Bootstrap Current ◽  
Ion Velocity

A novel derivation of the parallel ion velocity, and the bootstrap and Pfirsch–Schlüter currents in an imperfectly optimized (that is, almost omnigenous) stellarator magnetic field, $\boldsymbol{B}$ , is presented that somewhat more generally recovers expressions completely consistent with previous analytic results. However, it is also shown that, when the conventional radially local form of the drift kinetic equation is employed, the flow velocity and the bootstrap current acquire a spurious contribution proportional to $\unicode[STIX]{x1D714}/\unicode[STIX]{x1D708}$ , where $\unicode[STIX]{x1D714}$ denotes the $\boldsymbol{E}\times \boldsymbol{B}$ rotation frequency (due to the radial electric field $\boldsymbol{E}$ ) and $\unicode[STIX]{x1D708}$ the collision frequency. This contribution is particularly large in the $\sqrt{\unicode[STIX]{x1D708}}$ regime and at smaller collisionalities, where $\unicode[STIX]{x1D714}/\unicode[STIX]{x1D708}\gtrsim 1$ , and is presumably present in most numerical calculations, but it disappears if a more accurate drift kinetic equation is used.

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