Search Publications
Characterizing the limitations to the coupling between Saturn's ionosphere and middle magnetosphere
Ray, L. C.; Galand, M.; Fleshman, B. L. +1 more
Observations of Saturn's ultraviolet and infrared aurora show structures that, when traced along the planetary magnetic field, map to the inner, middle, and outer magnetosphere. From low to high latitudes the structures seen in the UV are the Enceladus footprint, which maps to an equatorial radius of 4 RS (Saturn radii); a diffuse emiss…
External triggering of plasmoid development at Saturn
Winglee, R. M.; Paty, C. S.; Harnett, E. M. +1 more
The Cassini spacecraft has encountered multiple plasmoids in Saturn's magnetotail thought to be produced by tail reconnection. However, single spacecraft measurements make it difficult to determine plasmoid size, where they form, the composition, and the geometry of the plasma sheet when plasmoids are produced. This paper examines these issues usi…
Statistical ring current of Saturn
Carbary, J. F.; Arridge, C. S.; Achilleos, N.
The statistical ring current of Saturn has been determined from the curl of the median magnetic field derived from over 5 years of observations of the Cassini magnetometer. The main issue addressed here is the calculation of the statistical ring current of Saturn by directly computing, for the first time, the symmetrical part of the ring current J…
Dynamic modeling of cusp ion structures
Raeder, J.; Trattner, K. J.; Connor, H. J.
Dispersed ion structures observed near the magnetosphere cusps have long been used to infer locations and properties of reconnection at the Earth's magnetopause. However, observations are often difficult to interpret since spacecraft move relative to a cusp ion structure, creating temporal and spatial ambiguity in the observations. Models of cusp …
Temporal evolution and electric potential structure of the auroral acceleration region from multispacecraft measurements
Dandouras, I.; Lucek, E.; Fazakerley, A. N. +12 more
Bright aurorae can be excited by the acceleration of electrons into the atmosphere in violation of ideal magnetohydrodynamics. Modeling studies predict that the accelerating electric potential consists of electric double layers at the boundaries of an acceleration region but observations suggest that particle acceleration occurs throughout this re…
Type II solar radio bursts: 2. Detailed comparison of theory with observations
Cairns, Iver H.; Robinson, P. A.; Hillan, D. S.
In this paper, the second in a two paper series, we quantitatively compare a detailed theory for type II solar radio bursts with observations and extract the parameters of the associated shocks. We use the techniques and assessment parameters developed and demonstrated in the companion paper for artificial data sets and solar wind models. Here we …
Is there long-range memory in solar activity on timescales shorter than the sunspot period?
Rypdal, M.; Rypdal, K.
The sunspot number (SSN), the total solar irradiance (TSI), a TSI reconstruction, and the solar flare index (SFI) are analyzed for long-range persistence (LRP). Standard Hurst analysis yields H ≈ 0.9, which suggests strong LRP. However, solar activity time series are nonstationary because of the almost-periodic 11 year smooth component, and the an…
Cluster multipoint study of the acceleration potential pattern and electrodynamics of an auroral surge and its associated horn arc
Lucek, E.; Nilsson, H.; Karlsson, T. +10 more
Cluster results are presented from the acceleration region of an auroral surge and connected horn arc, observed during an extended time period of substorm activity. The Cluster spacecraft crossed different magnetic local time (MLT) sectors of the surge and horn, with lag times of 2-10 min. Acceleration potential patterns are derived for the horn a…
The wide skirt of the bashful ballerina: Hemispheric asymmetry of the heliospheric magnetic field in the inner and outer heliosphere
Mursula, K.; Virtanen, I. I.
We reanalyze the observations of the heliospheric magnetic field (HMF) made by the Pioneer 10 and 11 and Voyager 1 and 2 heliospheric probes since 1972, and calculate the HMF sector occurrence ratios and tangential component strengths in the different regions of the heliosphere. Observations at the distant probes and at 1 AU show a very consistent…
Storm and substorm effects on magnetotail current sheet motion
Lester, M.; Milan, S. E.; Fear, R. C. +1 more
Passes through the mid-region of the magnetotail by the Cluster spacecraft from 2001 to 2007 have been examined to study the dynamics of the cross-tail current sheet. Cluster is ideally placed to study this region due to the orientation of the orbit in the magnetotail, such that the current sheet is sampled at distances downtail from about 8-19 R<…