TY  - JOUR
A1  - Park, Jaeheung
A1  - Lühr, Hermann
A1  - Kervalishvili, Guram N.
A1  - Rauberg, Jan
A1  - Michaelis, Ingo
A1  - Stolle, Claudia
A1  - Kwak, Young-Sil
T1  - Nighttime magnetic field fluctuations in the topside ionosphere at midlatitudes and their relation to medium-scale traveling ionospheric disturbances: The spatial structure and scale sizes
JF  - Journal of geophysical research : Space physics
N2  - Previous studies suggested that electric and/or magnetic field fluctuations observed in the nighttime topside ionosphere at midlatitudes generally originate from quiet time nocturnal medium-scale traveling ionospheric disturbances (MSTIDs). However, decisive evidences for the connection between the two have been missing. In this study we make use of the multispacecraft observations of midlatitude magnetic fluctuations (MMFs) in the nighttime topside ionosphere by the Swarm constellation. The analysis results show that the area hosting MMFs is elongated in the NW-SE (NE-SW) direction in the Northern (Southern) Hemisphere. The elongation direction and the magnetic field polarization support that the area hosting MMFs is nearly field aligned. All these properties of MMFs suggest that they have close relationship with MSTIDs. Expectation values of root-mean-square field-aligned currents associated with MMFs are up to about 4nA/m(2). MMF coherency significantly drops for longitudinal distances of 1 degrees.
KW  - midlatitude nighttime magnetic fluctuation
KW  - nighttime MSTID
KW  - Swarm constellation
Y1  - 2015
U6  - https://doi.org/10.1002/2015JA021315
SN  - 2169-9380
SN  - 2169-9402
VL  - 120
IS  - 8
SP  - 6818
EP  - 6830
PB  - American Geophysical Union
CY  - Washington
ER  - 
TY  - JOUR
A1  - Xiong, Chao
A1  - Stolle, Claudia
A1  - Luehr, Hermann
A1  - Park, Jaeheung
A1  - Fejer, Bela G.
A1  - Kervalishvili, Guram N.
T1  - Scale analysis of equatorial plasma irregularities derived from Swarm constellation
JF  - Earth, planets and space
N2  - In this study, we investigated the scale sizes of equatorial plasma irregularities (EPIs) using measurements from the Swarm satellites during its early mission and final constellation phases. We found that with longitudinal separation between Swarm satellites larger than 0.4 degrees, no significant correlation was found any more. This result suggests that EPI structures include plasma density scale sizes less than 44 km in the zonal direction. During the Swarm earlier mission phase, clearly better EPI correlations are obtained in the northern hemisphere, implying more fragmented irregularities in the southern hemisphere where the ambient magnetic field is low. The previously reported inverted-C shell structure of EPIs is generally confirmed by the Swarm observations in the northern hemisphere, but with various tilt angles. From the Swarm spacecrafts with zonal separations of about 150 km, we conclude that larger zonal scale sizes of irregularities exist during the early evening hours (around 1900 LT).
KW  - Equatorial plasma irregularities
KW  - Ionospheric scale lengths
KW  - Swarm constellation
Y1  - 2016
U6  - https://doi.org/10.1186/s40623-016-0502-5
SN  - 1880-5981
VL  - 68
SP  - 189
EP  - 202
PB  - Springer
CY  - Heidelberg
ER  -