The Helioseismic and Magnetic Imager (HMI) Investigation for the Solar Dynamics Observatory (SDO)

Scherrer, P. H.; Schou, J.; Bush, R. I.; Kosovichev, A. G.; Bogart, Ralph; Hoeksema, J. T.; Liu, Y.; Duvall, T. L.; Zhao, Junwei; Title, A. M.; Schrijver, Carolus J.; Tarbell, T. D.; Tomczyk, S.

doi:10.1007/s11207-011-9834-2

Cited by 2,098 publications

(1,368 citation statements)

References 43 publications

Supporting

Mentioning

1,316

Contrasting

Unclassified

Order By: Relevance

“…If we follow the relation ΔR R = −3 2 Δν ν , which would correspond to an upper limit for a change in solar radius of about 50 km at maximum of Cycle 23 and of about 30 km during Cycle 24. Bush et al (2015) extracted a radius change of 4 × 10 −5 over the last four years using the observations from the Helioseismic and Magnetic Imager (HMI; Scherrer et al 2012) instrument on board the Solar Dynamics Observatory spacecraft, which is compatible with the estimate extracted from the radial mode observed by the GOLF instrument. The l = 1 dipole and l = 2 quadrupole temporal variations shown in Fig.…”

Section: Discussionmentioning

confidence: 62%

Seismic sensitivity to sub-surface solar activity from 18 yr of GOLF/SoHO observations

Salabert

García

Turck‐Chièze

2015

A&A

View full text Add to dashboard Cite

Solar activity has significantly changed over the last two Schwabe cycles. After a long and deep minimum at the end of Cycle 23, the weaker activity of Cycle 24 contrasts with the previous cycles. In this work, the response of the solar acoustic oscillations to solar activity is used in order to provide insights into the structural and magnetic changes in the sub-surface layers of the Sun during this on-going unusual period of low activity. We analyze 18 yr of continuous observations of the solar acoustic oscillations collected by the Sun-as-a-star GOLF instrument on board the SoHO spacecraft. From the fitted mode frequencies, the temporal variability of the frequency shifts of the radial, dipolar, and quadrupolar modes are studied for different frequency ranges that are sensitive to different layers in the solar sub-surface interior. The low-frequency modes show nearly unchanged frequency shifts between Cycles 23 and 24, with a time evolving signature of the quasi-biennial oscillation, which is particularly visible for the quadrupole component revealing the presence of a complex magnetic structure. The modes at higher frequencies show frequency shifts that are 30% smaller during Cycle 24, which is in agreement with the decrease observed in the surface activity between Cycles 23 and 24. The analysis of 18 yr of GOLF oscillations indicates that the structural and magnetic changes responsible for the frequency shifts remained comparable between Cycle 23 and Cycle 24 in the deeper sub-surface layers below 1400 km as revealed by the low-frequency modes. The frequency shifts of the higher-frequency modes, sensitive to shallower regions, show that Cycle 24 is magnetically weaker in the upper layers of Sun.

show abstract

Section: Discussionmentioning

confidence: 62%

Seismic sensitivity to sub-surface solar activity from 18 yr of GOLF/SoHO observations

Salabert

García

Turck‐Chièze

2015

A&A

View full text Add to dashboard Cite

show abstract

“…All the images are corrected for the solar differential rotation. For the magnetograms, we use the data observed by the Helioseismic and Magnetic Imager (HMI, Scherrer et al 2012) on board the SDO. HMI measures the photospheric magnetic field of the Sun with a cadence of 45 s and a spatial resolution 1″.…”

Section: Instrumentation and Datamentioning

confidence: 99%

Peculiar Stationary Euv Wave Fronts in the Eruption on 2011 May 11

Chandra

Chen

Fulara

et al. 2016

ApJ

View full text Add to dashboard Cite

We present and interpret the observations of extreme ultraviolet (EUV) waves associated with a filament eruption on 2011 May 11. The filament eruption also produces a small B-class two ribbon flare and a coronal mass ejection. The event is observed by the Solar Dynamic Observatory with high spatio-temporal resolution data recorded by the Atmospheric Imaging Assembly. As the filament erupts, we observe two types of EUV waves (slow and fast) propagating outwards. The faster EUV wave has a propagation velocity of ∼500 km s −1 and the slower EUV wave has an initial velocity of ∼120 km s −1 . We report, for the first time, that not only does the slower EUV wave stop at a magnetic separatrix to form bright stationary fronts, but also the faster EUV wave transits a magnetic separatrix, leaving another stationary EUV front behind.

show abstract

“…Because there is a possibility − even if the event has no WL enhancements from the SOT data − that WL emission may exist out of the SOT field of view, we also checked the continuum data from the Helioseismic and Magnetic Imager (HMI) [29,30] onboard the Solar Dynamics Observatory (SDO) [31]. We found that both events had WL emission observed simultaneously by both instruments.…”

Section: Event Selectionmentioning

confidence: 99%

Capability of the accelerated protons as the origin of white-light emission of solar flare

Watanabe¹,

Masuda²,

Ohno³

2017

Proceedings of 35th International Cosmic Ray Conference — PoS(ICRC2017)

View full text Add to dashboard Cite

In association with strong solar flares, we sometimes observe enhancements of visible continuum radiation, which is known as a "white-light flare". As most white-light (WL) events show close correlations in time and location with hard X-rays and/or radio emission, there is some consensus that WL emission originates from accelerated particles, especially non-thermal electrons. One model proposes that WL is emitted near the photosphere; however, non-thermal electrons are thermalized in the chromosphere and cannot reach the photosphere. Thus, there is a problem: how can the energy of non-thermal electrons − and/or other accelerated particles such as high-energy protons − propagate to the photosphere and produce WL emission? In the present study, we investigate the possibility that accelerated protons may produce the WL emission of solar flares. We found 51 WL events observed by Hinode/SOT. Among them, gamma-rays with energies greater than 1 MeV were observed only in the X1.8-class flare on October 23, 2012 and in the M7.9-class flare on June 25, 2015. Focusing on these flare events, we compare the energetics of WL emission and of accelerated ion fluxes. We find that it is difficult for accelerated ions to provide sufficient energy to account for WL emission.

show abstract

The Helioseismic and Magnetic Imager (HMI) Investigation for the Solar Dynamics Observatory (SDO)

Cited by 2,098 publications

References 43 publications

Seismic sensitivity to sub-surface solar activity from 18 yr of GOLF/SoHO observations

Seismic sensitivity to sub-surface solar activity from 18 yr of GOLF/SoHO observations

Peculiar Stationary Euv Wave Fronts in the Eruption on 2011 May 11

Capability of the accelerated protons as the origin of white-light emission of solar flare

Contact Info

Product

Resources

About