@article{ParkLuehrKervalishvilietal.2015,
  author    = {Park, Jaeheung and L{\"u}hr, Hermann and Kervalishvili, Guram N. and Rauberg, Jan and Michaelis, Ingo and Stolle, Claudia and Kwak, Young-Sil},
  title     = {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},
  series = {Journal of geophysical research : Space physics},
  volume    = {120},
  journal   = {Journal of geophysical research : Space physics},
  number    = {8},
  publisher = {American Geophysical Union},
  address   = {Washington},
  issn      = {2169-9380},
  doi       = {10.1002/2015JA021315},
  pages     = {6818 -- 6830},
  year      = {2015},
  abstract  = {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.},
  language  = {en}
}
@article{ParkStolleXiongetal.2015,
  author    = {Park, Jaeheung and Stolle, Claudia and Xiong, Chao and L{\"u}hr, Hermann and Pfaff, Robert F. and Buchert, Stephan and Martinis, Carlos R.},
  title     = {A dayside plasma depletion observed at midlatitudes during quiet geomagnetic conditions},
  series = {Geophysical research letters},
  volume    = {42},
  journal   = {Geophysical research letters},
  number    = {4},
  publisher = {American Geophysical Union},
  address   = {Washington},
  issn      = {0094-8276},
  doi       = {10.1002/2014GL062655},
  pages     = {967 -- 974},
  year      = {2015},
  abstract  = {In this study we investigate a dayside, midlatitude plasma depletion (DMLPD) encountered on 22 May 2014 by the Swarm and GRACE satellites, as well as ground-based instruments. The DMLPD was observed near Puerto Rico by Swarm near 10 LT under quiet geomagnetic conditions at altitudes of 475-520 km and magnetic latitudes of similar to 25 degrees-30 degrees. The DMLPD was also revealed in total electron content observations by the Saint Croix station and by the GRACE satellites (430 km) near 16 LT and near the same geographic location. The unique Swarm constellation enables the horizontal tilt of the DMLPD to be measured (35 degrees clockwise from the geomagnetic east-west direction). Ground-based airglow images at Arecibo showed no evidence for plasma density depletions during the night prior to this dayside event. The C/NOFS equatorial satellite showed evidence for very modest plasma density depletions that had rotated into the morningside from nightside. However, the equatorial depletions do not appear related to the DMLPD, for which the magnetic apex height is about 2500 km. The origins of the DMLPD are unknown, but may be related to gravity waves.},
  language  = {en}
}