Surface Magnetism Effects in Time‐Distance Helioseismology

Surface Magnetism Effects in Time-Distance Helioseismology

Recent observations of helioseismic holography revealed that magnetic fields that are inclined relative to the line-of-sight direction could cause systematic variations in measured acoustic phase shifts (hereafter, “inclined magnetic field effect”), and that the presence of surface magnetic field may shift the phases and impair the coherence of acoustic waves (known as “showerglass effect”), th...

Diagnostics of Plasma Dynamics and Magnetism Inside the Sun by Helioseismology

Helioseismology observations from space missions SOHO and Hinode have provided tremendous amount of new information about thermodynamic properties and dynamics of plasma in the solar interior. The helioseismic diagnostics are based on measuring oscillation frequencies and travel times of acoustic waves excited by turbulent convection in subsurface layers. These diagnostics give us new insights ...

Magnetism of FePt surface alloys.

The complex correlation of structure and magnetism in highly coercive monoatomic FePt surface alloys is studied using scanning tunneling microscopy, x-ray magnetic circular dichroism, and ab initio theory. Depending on the specific lateral atomic coordination of Fe either hard magnetic properties comparable to that of bulk FePt or complex noncollinear magnetism due to Dzyaloshinski-Moriya inter...

Surface magnetism in iron, cobalt, and nickel.

Gravitational helioseismology?

The magnitudes of the external gravitational perturbations associated with the normal modes of the Sun are evaluated to determine whether these solar oscillations could be observed with the proposed Laser Interferometer Space Antenna (LISA), a network of satellites designed to detect gravitational radiation. The modes of relevance to LISA—the l = 2, low-order p, f and g-modes—have not been conc...