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Pseudo-field line resonances in ground Pc5 pulsation events

Sarafopoulos, D. V.

In this work we study four representative cases of Pc5 ground pulsation events with discrete and remarkably stable frequencies extended at least in a high-latitude range of ~20°; a feature that erroneously gives the impression for an oscillation mode with "one resonant field line". Additionally, the presented events show characteristic changes in …

Magnetospheric plasma boundaries: a test of the frozen-in magnetic field theorem

Lundin, R.; Yamauchi, M.; Sauvaud, J. -A. +1 more

The notion of frozen-in magnetic field originates from H. Alfvén, the result of a work on electromagnetic-hydrodynamic waves published in 1942. After that, the notion of frozen-in magnetic field, or ideal MHD, has become widely used in space plasma physics. The controversy on the applicability of ideal MHD started in the late 1950s and has continu…

Ab initio oscillator strengths and transition probabilities of transitions from 2s ²2p ²3l and 2s2p ³3l in S X

Karpuškienė, R.; Bogdanovich, P.; Udris, A.

Ab initio energy spectra of the ground configuration 2s ²2p ³ and the excited configurations 2s2p ⁴, 2p ⁵, 2s ²2p ²3s, 2s ²2p ²3p, 2s ²2p ²3d, 2s2p ³3s, 2s2p ³3p, and 2s2p ³3d of nitrogen-like sulphur S X h…

Nonradial and nonpolytropic astrophysical outflows. VII. Fitting ULYSSES solar wind data during minimum

Tsinganos, K.; Iro, N.; Lima, J. J. G. +1 more

Exact axisymmetric analytical solutions of the governing MHD equations for magnetized and rotating outflows are applied to the solar wind during solar minimum as observed by ULYSSES. Using the spacecraft data, the latitudinal dependences of physical quantities such as the density, velocity, magnetic field and temperature are analytically described…

CONFERENCES AND SYMPOSIA: A 'wild surmise': first results from the Huygens probe into Titan's atmosphere

Owen, Tobias; Niemann, Hasso; Atreya, Sushil

Model of the all-sky He II 30.4 nm solar flux

Auchère, F.; von Steiger, R.; Witte, M. +3 more

Because of the orbit characteristics of the vast majority of spacecraft, the solar flux has been generally measured at Earth or in the plane of the ecliptic. So far, most published studies did not consider the fact that the extreme ultraviolet (EUV) solar flux is largely anisotropic. Indeed, in the EUV, the distribution of very contrasted bright a…

Separating C Stars from Dust in the Central Region of the Seyfert 2 Galaxy NGC 1241

Díaz, Rubén J.; Dottori, Horacio; Carranza, Gustavo +2 more

The Seyfert 2 galaxy NGC 1241 presents a 1.5 kpc large circumnuclear ring (CNR) of star formation embracing a small bar plus leading arms. Those structures are Paα emitters but barely seen in Hα. It also presents stellar trailing arms inside the CNR. Gemini and HST imagery allow the construction of high-resolution (V-H) and (J-K_s) color…

Cluster scaling and its redshift evolution from XMM-Newton

Zhang, Y. -Y.; Finoguenov, A.; Böhringer, H. +4 more

We put together the results of XMM-Newton observations of a number of representative group and cluster samples at low and high redshifts. These results confirm the entropy ramp as an explanation of the observed scaling relations. We observe a mild evolution in the entropy of clusters. The observed degree of evolution is consistent with expectation…

Resonant Heating of Ions by Parallel Propagating Alfvén Waves in Solar Coronal Holes

Xiao, Chi-Jie; Wang, Jing-Xiu; Zhang, Tian-Xi

Resonant heating of H, O⁺⁵, and Mg⁺⁹ by parallel propagating ion-cyclotron Alfvén waves in solar coronal holes at a heliocentric distance is studied using the heating rate derived from the quasilinear theory. It is shown that the particle-Alfvén-wave interaction is a significant microscopic process. The temperatures of the io…

UX Ret and CN Hyi: hipparcos photometry analysis

Wadhwa, Surjit S.; Zealey, William J.

We present an analysis of the Hipparcos photometry of the contact binary systems UX Ret and CN Hyi. The Wilson-Devinney code is employed to model the V band light curve for several fixed values of the mass ratio. From the quality-of-fit of the different solutions a final solution is derived for each system. Absolute values of the system are derive…