Search Publications
Triple cusps observed by Cluster-Temporal or spatial effect?
Balogh, A.; Glassmeier, K. -H.; Zhang, H. +6 more
On April 18, 2002, the Cluster spacecraft were outbound in the northern hemisphere over the pole and entered the cusp. A cusp-like region was observed consecutively three times from 1620 to 1830 UT by all four Cluster Spacecraft although the solar wind dynamic pressure was small and stable. All three cusp encounters were characterized by turbulent…
Orientation and motion of a discontinuity from Cluster curlometer capability: Minimum variance of current density
Klecker, B.; Vaivads, A.; Dunlop, M. W. +4 more
A new technique to derive magnetopause key parameters such as orientation, velocity and thickness from multi-spacecraft observations is presented. The method is based on four-spacecraft determination of the current density, variance analysis to estimate the orientation and thereafter integration of the current density across the magnetopause to fi…
Seasonal change in Titan's haze 1992-2002 from Hubble Space Telescope observations
Lorenz, Ralph D.; Lemmon, Mark T.; Smith, Peter H.
Images from the Hubble Space Telescope (HST) document the seasonal migration of haze in Titan's atmosphere. Image profiles show darkening of the north relative to the south at 439 nm (blue) but no change at 619 nm. The limb profile at 889 nm has inverted, becoming north-bright, a variation consistent with haze transport towards the winter hemisphe…
The termination shock near 35° latitude
Burlaga, L. F.; Sheeley, N. R.; Wang, Y. -M. +1 more
The termination shock moves outwards and inwards over timescales of a solar cycle in response to the variations in the average solar wind speed. The amplitude is greater than 50 AU near 35° latitude; the maximum (minimum) distance occurs during the rising (declining) phase of the solar cycle. Shock parameters are distinctly different when the shoc…
Oblique propagation of 30 s period fast magnetosonic foreshock waves: A Cluster case study
Balogh, A.; Dandouras, I.; Eastwood, J. P. +2 more
It is accepted that the 30 s period Ultra-Low-Frequency waves observed in the terrestrial foreshock are generated by backstreaming ions through the ion-ion right hand instability. However, such waves are generally observed to propagate obliquely to the field, in direct contrast to theoretical predictions of parallel propagation. A case study, base…
Transient ion beamlet injections into spatially separated PSBL flux tubes observed by Cluster-CIS
Lundin, R.; Dandouras, I.; Klecker, B. +8 more
Ion measurements from Cluster-CIS were used to characterize and interpret the signatures of PSBL energy-dispersed ions and their fine structure. On 14 February 2001, several ion injections were encountered by SC 1 and SC 3, separated by ~530 km, during an outbound orbit at 4.5 RE. Both satellites recorded the same ion structures. The en…
Cluster observations of complex 3D magnetic structures at the magnetopause
Fedorov, A.; Budnik, E.; Balogh, A. +7 more
On June 30, 2001, around 0530 UT, Cluster was moving along the magnetopause with spacecraft on both sides of the discontinuity. The configuration was `quasi-ideal' with magnetic field and plasma flow almost aligned in the magnetosheath and nearly anti-parallel to the magnetospheric field. Cluster observed several perturbations with leading and tra…
Chemical composition of Titan's haze: Are PAHs present?
McKay, Christopher P.; Toon, Owen B.; Trainer, Melissa G. +4 more
Previous laboratory studies of haze aerosols analogous to those in Titan's atmosphere have shown evidence of the formation of polycyclic aromatic hydrocarbons (PAHs). If present, PAHs may provide a mechanism for both particle formation and nitrogen incorporation. We have conducted new experiments simulating Titan haze production using an Aerosol M…
Two examples of magnetic clouds with double rotations observed by the Ulysses spacecraft
Forsyth, R. J.; Rees, A.
A survey of Ulysses magnetometer data has been carried out between Oct 1990 (launch) and Apr 2003 (just after the second northern polar pass) cataloguing magnetic cloud (MC) signatures, i.e., a smooth magnetic field rotation and enhanced magnetic field magnitude. After confirming that each of these events was a true MC by checking for a low proton…
Discrete modes and turbulence in a wave-driven strongly magnetized plasma
Matthaeus, William H.; Lanzerotti, Louis J.; Dmitruk, Pablo
We show the coexistence of discrete modes and turbulence in numerical experiments of magnetohydrodynamics with a strong background magnetic field. The particular system we consider is a model of an open magnetic region which we have previously used in coronal heating studies. In the simulations shown here, Alfven waves at discrete frequencies with…