Search Publications
The Helioseismic and Magnetic Imager (HMI) Vector Magnetic Field Pipeline: Overview and Performance
Liu, Yang; Leka, K. D.; Hayashi, Keiji +9 more
The Helioseismic and Magnetic Imager (HMI) began near-continuous full-disk solar measurements on 1 May 2010 from the Solar Dynamics Observatory (SDO). An automated processing pipeline keeps pace with observations to produce observable quantities, including the photospheric vector magnetic field, from sequences of filtergrams. The basic vector-fiel…
The magnetic field in the solar atmosphere
Solanki, Sami K.; Wiegelmann, Thomas; Thalmann, Julia K.
This publication provides an overview of magnetic fields in the solar atmosphere with the focus lying on the corona. The solar magnetic field couples the solar interior with the visible surface of the Sun and with its atmosphere. It is also responsible for all solar activity in its numerous manifestations. Thus, dynamic phenomena such as coronal m…
An Interface Region Imaging Spectrograph First View on Solar Spicules
Golub, L.; Tian, H.; De Pontieu, B. +17 more
Solar spicules have eluded modelers and observers for decades. Since the discovery of the more energetic type II, spicules have become a heated topic but their contribution to the energy balance of the low solar atmosphere remains unknown. Here we give a first glimpse of what quiet-Sun spicules look like when observed with NASA's recently launched…
Characterizing and predicting the magnetic environment leading to solar eruptions
Amari, Tahar; Canou, Aurélien; Aly, Jean-Jacques
The physical mechanism responsible for coronal mass ejections has been uncertain for many years, in large part because of the difficulty of knowing the three-dimensional magnetic field in the low corona. Two possible models have emerged. In the first, a twisted flux rope moves out of equilibrium or becomes unstable, and the subsequent reconnection…
Formation of a Double-decker Magnetic Flux Rope in the Sigmoidal Solar Active Region 11520
Cheng, X.; Ding, M. D.; Zhang, J. +5 more
In this paper, we address the formation of a magnetic flux rope (MFR) that erupted on 2012 July 12 and caused a strong geomagnetic storm event on July 15. Through analyzing the long-term evolution of the associated active region observed by the Atmospheric Imaging Assembly and the Helioseismic and Magnetic Imager on board the Solar Dynamics Observ…
Imaging and Spectroscopic Observations of a Filament Channel and the Implications for the Nature of Counter-streamings
Chen, P. F.; Harra, L. K.; Fang, C.
The dynamics of a filament channel are observed with imaging and spectroscopic telescopes before and during the filament eruption on 2011 January 29. The extreme ultraviolet (EUV) spectral observations reveal that there are no EUV counterparts of the Hα counter-streamings in the filament channel, implying that the ubiquitous Hα counter-streamings …
The Radiated Energy Budget of Chromospheric Plasma in a Major Solar Flare Deduced from Multi-wavelength Observations
Chamberlin, Phillip C.; Milligan, Ryan O.; Kerr, Graham S. +7 more
This paper presents measurements of the energy radiated by the lower solar atmosphere, at optical, UV, and EUV wavelengths, during an X-class solar flare (SOL2011-02-15T01:56) in response to an injection of energy assumed to be in the form of nonthermal electrons. Hard X-ray observations from RHESSI were used to track the evolution of the paramete…
The Solar Internetwork. I. Contribution to the Network Magnetic Flux
Gošić, M.; Bellot Rubio, L. R.; Katsukawa, Y. +2 more
The magnetic network (NE) observed on the solar surface harbors a sizable fraction of the total quiet Sun flux. However, its origin and maintenance are not well known. Here we investigate the contribution of internetwork (IN) magnetic fields to the NE flux. IN fields permeate the interior of supergranular cells and show large emergence rates. We u…
Photometric and Thermal Cross-calibration of Solar EUV Instruments
Schrijver, C. J.; Testa, P.; Warren, H. +2 more
We present an assessment of the accuracy of the calibration measurements and atomic physics models that go into calculating the SDO/AIA response as a function of wavelength and temperature. The wavelength response is tested by convolving SDO/EVE and Hinode/EIS spectral data with the AIA effective area functions and by comparing the predictions wit…
Solar Dynamics Observatory and Hinode Observations of a Blowout Jet in a Coronal Hole
Young, P. R.; Muglach, K.
A blowout jet occurred within the south coronal hole on 9 February 2011 at 09:00 UT and was observed by the Atmospheric Imaging Assembly (AIA) and Helioseismic and Magnetic Imager (HMI) onboard the Solar Dynamics Observatory, and by the EUV Imaging Spectrometer (EIS) and X-Ray Telescope (XRT) onboard the Hinode spacecraft during coronal-hole monit…