Magnetopause reconnection is a process whereby the Sun explosively transfers energy to the Earth. Whether the process is spatially patchy or spatially continuous and extended has been under long debate. We use space–ground coordination to overcome the limitations of previous studies and reliably interpret spatial extent. Our result strongly indicates that both patchy and extended reconnection is possible and, interestingly, that extended reconnection grows from a localized patch via spreading.

The comparison of geomagnetic active and quite events of double substorm onsets responsive to IMF variations shows that the occurrence sequence of all required substorm signatures looks the same and not different for small and large Kp. Double substorm onsets responsive to IMF variations can be characterized with two-stage magnetic dipolarizations in the magnetotail, two auroral breakups of which the first occurring at lower latitudes than the second, and two consecutive Pi2-Ps6 band pulsations.

We employ multipoint observations of the Van Allen Probes, THEMIS, GOES and Cluster to present case and statistical studies of the electromagnetic field, plasma and particle response to interplanetary (IP) shocks observed by Wind. We perform a statistical study of E_y variations of the electric field and associated plasma drift flow velocities for 60 magnetospheric events during the passage of interplanetary shocks.

The solar wind reshapes Earth's magnetic field to create our magnetosphere and powers many dynamic processes in our plasma-filled environment, some of which produce the aurora. Networks of ground-based all-sky cameras are valuable tools that offer a large field-of-view with which to study the aurora. Using sequences of auroral images, this study defines criteria for differentiating an important type of aurora whose subcategories are often conflated.

The spatial and temporal evolution of the aurora provides information about plasma dynamics throughout the magnetosphere. The THEMIS all-sky imager network has been operating for over 10 years and has accumulated millions of auroral images. To speed the extraction of information from this dataset, it is desirable to implement automated algorithms to track and classify the aurora. This paper demonstrates an automatic method of extracting the motion of the aurora from sequences of images.

Hot flow anomalies (HFAs) at Earth's bow shock were identified in Time History of Events and Macroscale Interactions During Substorms (THEMIS) satellite data from 2007 to 2009. The events were classified as young or mature and regular or spontaneous hot flow anomalies (SHFAs). HFA–SHFA occurrence decreases with distance upstream from the bow shock. HFAs are more prevalent for radial interplanetary magnetic fields and solar wind speeds from 550 to 600 km^s−1.

This is the first statistical study of the motion of patchy pulsating aurora (PPA). Our results show that PPA patches mainly drift eastward after midnight and westward before midnight, which suggests that the drifts of auroral patches could be a proxy for the ionospheric convection and provide a convenient and accurate method to remotely sense the magnetospheric convection. We also found that patch velocities do not seem to depend on AE index.

In order to compare auroral observations, it is necessary to ensure that all instruments are properly calibrated. This can be difficult to achieve with different instruments operated for extended intervals at remote field sites under harsh conditions. Astronomical sources can be used for independent absolute calibration procedures. Under ideal conditions Jupiter is an excellent source, as it can provide more light than the brightest star. We use Jupiter to calibrate an auroral MSP network.

Rapid fluctuations in amplitude and phase of radio waves passing through the ionosphere degrade GPS positional accuracy and can lead to navigational errors, particularly during geomagnetic storms. As a function of magnetic latitude and local time, regions of GPS phase scintillation at high latitudes are identified in the context of coupling between the solar wind and the magnetosphere-ionosphere system, which primarily depends on the interplanetary magnetic field magnitude and orientation.