Identification

Title

Spectropolarimetry of the Solar Mg II h and k Lines

Abstract

We report on spectropolarimetric observations across the Mg ii h and k lines at 2800 Å made by the Ultraviolet Spectrometer and Polarimeter on board the Solar Maximum Mission satellite. Our analysis confirms the strong linear polarization in the wings of both lines observed near the limb, as previously reported, but also demonstrates the presence of a negatively (i.e., radially oriented) polarized signal between the two lines. We find evidence for fluctuations of the polarization pattern over a broad spectral range, resulting in some depolarization with respect to the pure scattering case when observed at very low spatial and temporal resolutions. This is consistent with recent theoretical modeling that predicts this to be the result of redistribution effects, quantum interference between the atomic levels of the upper term, and magneto-optical effects. A first attempt at a quantitative exploitation of these signals for the diagnosis of magnetic fields in the chromosphere is attempted. In active regions, we present observations of circular polarization dominated by the Zeeman effect. We are able to constrain the magnetic field strength in the upper active chromosphere using an analysis based on the magnetograph formula, as justified by theoretical modeling. We inferred a significantly strong magnetic field (~500 G) at the 2.5σ level on an exceptionally active, flaring region.

Resource type

document

Resource locator

Unique resource identifier

code

https://n2t.org/ark:/85065/d7nv9nd9

codeSpace

Dataset language

eng

Spatial reference system

code identifying the spatial reference system

Classification of spatial data and services

Topic category

geoscientificInformation

Keywords

Keyword set

keyword value

Text

originating controlled vocabulary

title

Resource Type

reference date

date type

publication

effective date

2016-01-01T00:00:00Z

Geographic location

West bounding longitude

East bounding longitude

North bounding latitude

South bounding latitude

Temporal reference

Temporal extent

Begin position

End position

Dataset reference date

date type

publication

effective date

2019-10-01T00:00:00Z

Frequency of update

Quality and validity

Lineage

Conformity

Data format

name of format

version of format

Constraints related to access and use

Constraint set

Use constraints

Limitations on public access

None

Responsible organisations

Responsible party

contact position

OpenSky Support

organisation name

UCAR/NCAR - Library

full postal address

PO Box 3000

Boulder

80307-3000

email address

opensky@ucar.edu

web address

http://opensky.ucar.edu/

name: homepage

responsible party role

pointOfContact

Metadata on metadata

Metadata point of contact