Search Publications
Effects from dayside magnetosphere to distant tail unleashed by a bifurcated, non-reconnecting interplanetary current sheet
Berchem, J.; Wing, S.; Farrugia, C. J. +6 more
Global magnetospheric effects resulting from the passage at Earth of large-scale structures have been well studied. The effects of common and short-term features, such as discontinuities and current sheets (CSs), have not been studied in the same depth. Herein we show how a seemingly unremarkable interplanetary feature can cause widespread effects…
Comparing Quasi-Parallel and Quasi-Perpendicular Configuration in the Terrestrial Magnetosheath: Multifractal Analysis
Sorriso-Valvo, Luca; Burgess, David; Yordanova, Emiliya +4 more
The terrestrial magnetosheath is characterized by large-amplitude magnetic field fluctuations. In some regions, and depending on the bow-shock geometry, these can be observed on several scales, and show the typical signatures of magnetohydrodynamic turbulence. Using Cluster data, magnetic field spectra and flatness are observed in two intervals se…
Data Mining Reconstruction of Magnetotail Reconnection and Implications for Its First-Principle Modeling
Sitnov, Mikhail; Stephens, Grant; Motoba, Tetsuo +1 more
Magnetic reconnection is a fundamental process providing topological changes of the magnetic field, reconfiguration of space plasmas and release of energy in key space weather phenomena, solar flares, coronal mass ejections and magnetospheric substorms. Its multiscale nature is difficult to study in observations because of their sparsity. Here we …
Concurrent empirical magnetic reconstruction of storm and substorm spatial scales using data mining and virtual spacecraft
Stephens, Grant K.; Sitnov, Mikhail I.
Data-mining (DM) has ushered in a new era of empirical magnetic reconstructions of the 4 magnetosphere via application of the k-nearest neighbors (kNN) method. In this approach, 5 the combined magnetosphere storm-substorm state is characterized by the Sym-H and AL IMF 6 indices, their time derivatives, and the solar wind electric field vBz . Howev…
Kelvin-Helmholtz Instability Associated with Reconnection and Ultra Low Frequency Waves at the Ground: A Case Study
Grigorenko, E. E.; Kronberg, E. A.; Nykyri, K. +7 more
The Kelvin-Helmholtz instability (KHI) and its effects relating to the transfer of energy and mass from the solar wind into the magnetosphere remain an important focus of magnetospheric physics. One such effect is the generation of Pc4-Pc5 ultra low frequency (ULF) waves (periods of 45-600 s). On 3 July 2007 at ~0500 magnetic local time the Cluste…
On the Origin of High–Frequency Magnetic Fluctuations in the Interplanetary Medium: A Brownian–like Approach
Vecchio, Antonio; Chiappetta, Federica; Lepreti, Fabio +2 more
Low–frequency fluctuations in the interplanetary medium have been extensively investigated and described in the framework of turbulence, and the observed universal scaling behavior represents a clear signature of the underlying energy cascade. On the contrary, the interpretation of observations of plasma fluctuations at high frequencies, where wav…
High-latitude cold ion outflow inferred from the Cluster wake observations in the magnetotail lobes and the polar cap region
André, Mats; Li, Kun; Wei, Yong +3 more
Cold ions with low (a few eV) thermal energies and also often low bulk drift energies, dominate the ion population in the Earth's magnetosphere. These ions mainly originate from the ionosphere. Here we concentrate on cold ions in the high latitude polar regions, where magnetic field lines are open and connected to the magnetotail. Outflow from the…
AME: A Cross-scale Constellation of CubeSats to Explore Magnetic Reconnection in the Solar-Terrestrial Relation
Dunlop, Malcolm; Khotyaintsev, Yuri; Phan, Tai +25 more
A major subset of solar-terrestrial relations, responsible in particular for the driver of space weather phenomena, is the interaction between the Earth's magnetosphere and the solar wind. As one of the most important modes of the solar-wind-magnetosphere interaction, magnetic reconnection regulates the energy transport and energy release in the s…
A Note on Capon's Minimum Variance Projection for Multi-Spacecraft Data Analysis
Narita, Yasuhito
Capon's minimum variance projection for the multi-point measurements is revisited using the method of likelihood function to derive the minimum variance projection and a simplified error estimate analytically. Theoretical construction of the minimum variance projection assumes a Gaussian form of the likelihood function and also regards the data co…
Ion-Scale Sideband Waves and Filament Formation: Alfvénic Impact on Heliospheric Plasma Turbulence
Motschmann, Uwe; Narita, Yasuhito
A mini-review is given about two recent discoveries in the solar wind turbulence research on ion-kinetic scales: the existence of sideband waves (or breakdown of the linear mode wave picture) and the wavevector anisotropy leading to a persistent filament formation in a wide range of plasma beta.