scholarly journals Stratification of east-west plasma flow channels observed in the ionospheric cusp in response to IMF BYpolarity changes

2010 ◽  
Vol 37 (13) ◽  
pp. n/a-n/a ◽  
Author(s):  
Y. Rinne ◽  
J. Moen ◽  
H. C. Carlson ◽  
M. R. Hairston
Keyword(s):  
Plasma Flow ◽  
Flow Channels ◽  
East West

scholarly journals Plasma flow channels with ULF waves observed by Cluster and Double Star

2005 ◽  
Vol 23 (8) ◽  
pp. 2929-2935 ◽  
Author(s):  
M. Volwerk ◽  
T. L. Zhang ◽  
R. Nakamura ◽  
A. Runov ◽  
W. Baumjohann ◽  
...  
Keyword(s):  
Magnetic Structure ◽  
Plasma Flow ◽  
Large Scale ◽  
Double Star ◽  
Flow Channel ◽  
Propagation Direction ◽  
Ulf Waves ◽  
Flow Channels ◽  
Earthward Flow

Abstract. On 14 August 2004 a large-scale magnetic structure was observed by Double Star TC-1 in the southern lobe and by Cluster in the northern lobe of the magnetotail. The structure has the signature of a (localized) dipolarization, decreasing Bx accompanied by an increasing Bz and a strong earthward flow. The propagation direction of this structure, however, seems to be more in the dawnward direction than earthward. The structure is accompanied by ULF waves with a period of ~5 min, which are simultaneously observed by the ground magnetometer station DIK, at the magnetic footpoints of the spacecraft. We interprete these waves as modes driven by the plasma flow and propagating in the flow channel.

scholarly journals Vortex Structure in the Plasma Flow Channels of the Venus Wake

10.5772/66762 ◽  
2017 ◽  
Author(s):  
Héctor Pérez-de-Tejada ◽  
Rickard Lundin ◽  
Devrie S. Intriligator
Keyword(s):  
Plasma Flow ◽  
Vortex Structure ◽  
Flow Channels

scholarly journals Poleward moving auroral forms (PMAFs) revisited: responses of aurorae, plasma convection and Birkeland currents in the pre- and postnoon sectors under positive and negative IMF <I>B<sub>y</sub></I> conditions

2007 ◽  
Vol 25 (7) ◽  
pp. 1629-1652 ◽  
Author(s):  
P. E. Sandholt ◽  
C. J. Farrugia
Keyword(s):  
Dynamical Evolution ◽  
Plasma Convection ◽  
Ion Drift ◽  
Flow Vorticity ◽  
Flow Channels ◽  
Major Interest ◽  
First Time ◽  
East West ◽  
Birkeland Currents ◽  
The Imf

Abstract. Using five case studies, we investigate the dynamical evolution of dayside auroral precipitation in relation to plasma convection, classifying it by the IMF By component and position with respect to noon. Auroral observations were made by meridian scanning photometers (MSPs) and an all-sky camera (ASC) in Ny Ålesund, Svalbard at 76° MLAT, while the spatial structure of the ionospheric plasma convection is inferred from SuperDARN radars and ion drift observations from spacecraft in polar orbit. The IMF configuration of major interest here is one pointing southward and with a dominant east-west component. Our emphasis is on the auroral phenomenon of PMAFs (poleward moving auroral forms), which are ionospheric signatures of pulsed reconnection at the magnetopause. We distinguish between PMAFs/prenoon and PMAFs/postnoon. These two activities are found to be separated by an auroral form around noon with attenuated emission at 630.0 nm. We document for the first time that this "midday gap aurora" appears in the form of a midday auroral brightening sequence (MABS). We study the PMAF activity consisting of an initial brightening phase and the later stages of PMAF evolution in relation to plasma convection cells, flow vorticity, and precipitation boundaries in the prenoon and postnoon sectors for both By polarities. Flow channels (PIFs) associated with PMAFs are strengthened by polarization effects at auroral boundaries. Addressing the implications of our proposed, extended perspective on dayside auroral morphology under southeast/west IMF for M-I coupling associated with pulsed magnetopause reconnection (FTEs), we draw inferences on the MLT-dependent geoeffectiveness (Birkeland current/auroral intensity) of magnetopause FTEs (subsolar region versus flanks).

scholarly journals A comparison of optical and coherent HF radar backscatter observations of a post-midnight aurora

1997 ◽  
Vol 15 (11) ◽  
pp. 1388-1398 ◽  
Author(s):  
S. E. Milan ◽  
M. Lester ◽  
J. Moen
Keyword(s):  
Flow Velocity ◽  
Plasma Flow ◽  
Hf Radar ◽  
Polar Cap ◽  
Common Features ◽  
Optical Feature ◽  
Radar Measurements ◽  
Coherent Backscatter ◽  
East West ◽  
Poleward Expansion

Abstract. A poleward-progressing 630 nm optical feature is observed between approximately 0100 UT and 0230 UT (0400 MLT to 0530 MLT) by a meridian-scanning photometer (MSP) located at Ny Ålesund, Svalbard. Simultaneous coherent HF radar measurements indicate a region of poleward-expanding backscatter with rapid sunward plasma flow velocity along the MSP meridian. Spatial maps of the backscatter indicate a stationary backscatter feature aligned obliquely with respect to the MSP meridian, which produces an impression of poleward-expansion as the MSP progresses to later MLT. Two interpretations of the observations are possible, depending on whether the arc system is considered to move (time-dependent) or to be stationary in time and apparent motion is produced as the MSP meridian rotates underneath it (time-independent). The first interpretation is as a poleward motion of an east-west aligned auroral arc. In this case the appearance of the region of backscatter is not associated with the optical feature, though the velocities within it are enhanced when the two are co-located. The second interpretation is as a polar arc or theta aurora, common features of the polar cap under the prevailing IMF northwards conditions. In this case the backscatter appears as an approximately 150 km wide region adjacent to the optical arc. In both interpretations the luminosity of the optical feature appears related to the magnitude of the plasma flow velocity. The optical features presented here do not generate appreciable HF coherent backscatter, and are only identifiable in the backscatter data as a modification of the flow by the arc electrodynamics.

Values and intergroup perceptions of East Germans and West Germans in 1998 1This research was supported by a grant from the German Research Society (We 1106/3-1).

1999 ◽  
Vol 58 (4) ◽  
pp. 263-272
Author(s):  
Jörg Doll ◽  
Michael Dick
Keyword(s):  
Research Society ◽  
Frame Of Reference ◽  
Control Group ◽  
Perceived Similarity ◽  
The West ◽  
Need For Uniqueness ◽  
German Research ◽  
East German ◽  
Experimental Group ◽  
East West

The studies reported here focus on similarities and dissimilarities between the terminal value hierarchies ( Rokeach, 1973 ) ascribed to different groups ( Schwartz & Struch, 1990 ). In Study 1, n = 65 East Germans and n = 110 West Germans mutually assess the respective ingroup and outgroup. In this intra-German comparison the West Germans, with a mean intraindividual correlation of rho = 0.609, perceive a significantly greater East-West similarity between the group-related value hierarchies than the East Germans, with a mean rho = 0.400. Study 2 gives East German subjects either a Swiss (n = 58) or Polish (n = 59) frame of reference in the comparison between the categories German and East German. Whereas the Swiss frame of reference should arouse a need for uniqueness, the Polish frame of reference should arouse a need for similarity. In accordance with expectations, the Swiss frame of reference significantly reduces the correlative similarity between German and East German from a mean rho = 0.703 in a control group (n = 59) to a mean rho = 0.518 in the experimental group. Contrary to expectations, the Polish frame of reference does not lead to an increase in perceived similarity (mean rho = 0.712).

OPTIMISATION OF THE CHARACTERISTICS OF THE PLASMA FLOW FROM A DIELECTRIC CHAMBER

1979 ◽  
Vol 40 (C7) ◽  
pp. C7-349-C7-350
Author(s):  
I. I. Egorov ◽  
L. N. Lesnevsky ◽  
G. A. Popov ◽  
A. G. Sobol ◽  
V. N. Turin
Keyword(s):  
Plasma Flow
Sign in / Sign up

Export Citation Format

Share Document