Search Publications
Evaluation of bispectrum in the wave number domain based on multi-point measurements
Glassmeier, K. -H.; Décréau, P. M. E.; Narita, Y. +3 more
We present an estimator of the bispectrum, a measure of three-wave couplings. It is evaluated directly in the wave number domain using a limited number of detectors. The ability of the bispectrum estimator is examined numerically and then it is applied to fluctuations of magnetic field and electron density in the terrestrial foreshock region obser…
Diagnostics of active and eruptive prominences through hydrogen and helium lines modelling
Vial, J. -C.; Labrosse, N.; Gouttebroze, P.
In this study we show how hydrogen and helium lines modelling can be used to make a diagnostic of active and eruptive prominences. One motivation for this work is to identify the physical conditions during prominence activation and eruption. Hydrogen and helium lines are key in probing different parts of the prominence structure and inferring the …
Multi-instrument observations of a large scale Pc4 pulsation
Lucek, E. A.; Yeoman, T. K.; Clausen, L. B. N. +1 more
On 7 November 2005 various ground based and spaced based instruments registered five wave packets with frequencies in the Pc4 range. The most prominent of the five wave packets was observed in ground based magnetometer data spanning almost all latitudes on the dayside magnetosphere. The propagation from the dayside into the tail is deduced from Po…
Tailward propagation of Pi2 waves in the Earth's magnetotail lobe
Balogh, A.; Nakamura, R.; Baumjohann, W. +3 more
Pi2 waves are an intergral part of the substorm process and have been observed on the ground and in space. Using the special ability of Cluster to determine the propagation direction of signals measured in the magnetometer data, it is found that in the lobes of the Earth's magnetotail, for the cases in this study, the Pi2 waves are travelling tail…
Iterative inversion of global magnetospheric ion distributions using energetic neutral atom (ENA) images recorded by the NUADU/TC2 instrument
Barabash, S.; Dandouras, I.; Cao, J. B. +9 more
A method has been developed for extracting magnetospheric ion distributions from Energetic Neutral Atom (ENA) measurements made by the NUADU instrument on the TC-2 spacecraft. Based on a constrained linear inversion, this iterative technique is suitable for use in the case of an ENA image measurement, featuring a sharply peaked spatial distributio…
Periodic traveling compression regions during quiet geomagnetic conditions and their association with ground Pi2
Dandouras, I.; Lucek, E.; Hasegawa, H. +5 more
Recently, Keiling et al. (2006) showed that periodic (~90 s) traveling compression regions (TCRs) during a substorm had properties of Pi2 pulsations, prompting them to call this type of periodic TCRs "lobe Pi2". It was further shown that time-delayed ground Pi2 had the same period as the lobe Pi2 located at 16 RE, and it was concluded t…
Nonlinear low-frequency wave aspect of foreshock density holes
Rème, H.; Parks, G. K.; Lin, N. +3 more
Recent observations have uncovered short-duration density holes in the Earth's foreshock region. There is evidence that the formation of density holes involves non-linear growth of fluctuations in the magnetic field and plasma density, which results in shock-like boundaries followed by a decrease in both density and magnetic field. In this study w…
Locating the solar source of 13 April 2006 magnetic cloud
van Driel-Gesztelyi, L.; Owen, C. J.; Démoulin, P. +5 more
Using Advanced Composition Explorer (ACE) in situ data we identify and describe an interplanetary magnetic cloud (MC) observed near Earth on 13 April 2006. We also use multi-instrument and multi-wavelength observations from the Solar and Heliospheric Observatory (SOHO), the Transition Region and Coronal Explorer (TRACE) and ground-based solar obse…
Sunward propagating Pc5 waves observed on the post-midnight magnetospheric flank
Glassmeier, K. -H.; Blomberg, L. G.; Schaefer, S. +1 more
The overall focus on the driver of toroidal Pc5 waves has been on processes located at or acting on the dayside magnetopause and dayside flanks of the magnetosphere. These processes can generate waves that propagate tailward in the magnetosphere. However, an increasing number of studies, both theoretical and experimental, have looked at waves prop…
Blob formation and acceleration in the solar wind: role of converging flows and viscosity
Lapenta, G.; Restante, A. L.
The effect of viscosity and of converging flows on the formation of blobs in the slow solar wind is analysed by means of resistive MHD simulations. The regions above coronal streamers where blobs are formed (Sheeley et al., 1997) are simulated using a model previously proposed by Einaudi et al. (1999). The result of our investigation is two-fold. …