We have studied the properties of a linear magnetic hole (LMH) with a size between typical ion and electron scales in the current sheet

A thin current formed by a strong electron flow on the outermost boundary of the LMH wrap most of the trapped electrons

The electric field occurs at the sharp boundary, possibly originating from the variation of the ion and electron gyrations at the boundary

We compare the auroral poleward boundary determined using simultaneous optical and particle data during different geomagnetic conditions

We find good agreement between the auroral boundary determined by auroral luminosity and those determined by particle flux

Luminosity method can be applied during active geomagnetic conditions, providing high spatial and temporal resolution polar cap boundary

We present height profiles of horizontal winds in the space-atmosphere interaction region where measurements have previously been difficult

Height profiles from both this technique and chemical tracers are not consistent with the HWM-14 model

Applying this approach to two years of data from two sites showed no indication of cusp-region forcing penetrating down to E-region heights

First Time-dependent multi-stream electron transport calculations are presented

Intensity modulation variations for emissions at 4278, 6730, 7774 and 8448 Å during flickering aurora are compared

Time-shift between column emission rates at 4278, 6730, 7774 and 8448 Å are predicted

The ROTI enhancement occurs three times over South America in the post-sunset, pre-midnight, and post-midnight sectors during the storm

The ROTI enhancements appear with a longitudinal extent of ∼20° in the equatorial ionosphere

The second ROTI enhancement is caused by the prompt penetration of an over-shielding electric field into the equator after a substorm

Intense near-equatorial whistler-mode waves are observed in conjunction with energetic electron precipitation measured by ELFIN

Test particle simulations are employed to directly compare observations with theory of non-linear wave particle resonant interactions

Precipitating electrons up to relativistic energies are likely due to resonant scattering extending up to 40° in latitude

The properties associated with magnetic switchbacks evolve with radial distance

Density compressions at the leading edge of switchbacks are correlated with velocity differences between fast plasma and ambient solar wind

The density compressions associated with magnetic switchbacks are consistent with magnetic field surrounding a fast ejecta

Seven simultaneous wind profiles in the lower thermosphere, horizontally separated by up to 600 km, are dominated by strong tides

A large-scale upward propagating inertia-gravity wave is evident in the observations

The region between 100 and 110 km shows the largest mesoscale variability of winds and wind shears, independent of separation scale

Slow-mode shocks can be detected from ∼9 , and their detection increases with increasing plasma beta and the distance from the X-point

The slow-mode shock detection percentage can drop to as low as ∼10% if the crossing angle of the satellite is very oblique

Close to the X-point ( 45 ), the classical picture of slow-mode shocks is valid, as they directly accelerate the downstream population

Electron inflow is accelerated by parallel electric field and mirror force, and decelerated by the gradient of parallel electron pressure

Parallel electric field plays a major role in the formation of electron inflow, while the contribution of mirror force cannot be ignored

The contributions of parallel electric field and mirror force change with the background plasma density and temperature