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Astrophysics and Astronomy

Dartmouth College

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Magnetic field

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Articles 1 - 3 of 3

Full-Text Articles in Physics

More About Arc-Polarized Structures In The Solar Wind, S A. Haaland, B Sonnerup, G Paschmann May 2012

More About Arc-Polarized Structures In The Solar Wind, S A. Haaland, B Sonnerup, G Paschmann

Dartmouth Scholarship

We report results from a Cluster-based study of the properties of 28 arc-polarized magnetic structures (also called rotational discontinuities) in the solar wind. These Alfve ́nic events were selected from the database created and analyzed by Knetter (2005) by use of criteria chosen to elim- inate ambiguous cases. His studies showed that standard, four-spacecraft timing analysis in most cases lacks sufficient accuracy to identify the small normal magnetic field compo- nents expected to accompany such structures, leaving unan- swered the question of their existence. Our study aims to break this impasse. By careful application of minimum vari- ance analysis of …


On Arc-Polarized Structures In The Solar Wind, B U. Sonnerup, S E. Haaland, G Paschmann Jun 2010

On Arc-Polarized Structures In The Solar Wind, B U. Sonnerup, S E. Haaland, G Paschmann

Dartmouth Scholarship

A theoretical model is proposed to account for some of the behavior of arc-polarized magnetic structures seen in the solar wind. To this end, an exact analytical solu- tion is developed that describes infinite plane wave trains of arbitrary amplitude in a plasma governed by ideal Hall MHD. The main focus is on intermediate-mode wave trains, which display double-branched magnetic hodogram signatures sim- ilar to those seen in the solar wind. The theoretically derived hodograms have field rotation in the ion-polarized sense at a slightly depressed field magnitude on one branch and an electron-polarized rotation at a slightly enhanced field …


The Structure Of Flux Transfer Events Recovered From Cluster Data, H Hasegawa, B U. Ö Sonnerup, C J. Owen, B Klecker, G Paschmann, A Balogh, H Re`Me Mar 2006

The Structure Of Flux Transfer Events Recovered From Cluster Data, H Hasegawa, B U. Ö Sonnerup, C J. Owen, B Klecker, G Paschmann, A Balogh, H Re`Me

Dartmouth Scholarship

The structure and formation mechanism of a to- tal of five Flux Transfer Events (FTEs), encountered on the equatorward side of the northern cusp by the Cluster space- craft, with separation of ∼5000 km, are studied by apply- ing the Grad-Shafranov (GS) reconstruction technique to the events. The technique generates a magnetic field/plasma map of the FTE cross section, using combined magnetic field and plasma data from all four spacecraft, under the assump- tion that the structure is two-dimensional (2-D) and time- independent. The reconstructed FTEs consist of one or more magnetic flux ropes embedded in the magnetopause, suggest- ing …