Ephemeral Regions on a Sequence of Full-Disk Michelson Doppler Imager Magnetograms

By H. Hagenaar. 2001

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Subfields: Astronomy and Astrophysics, Molecular Biology

View Paper: https://www.semanticscholar.org/paper/aaa293deb3a44c8a61e7c84f42fd5c6fad01f0d6

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Citations in the corpus

The Solar Cycle (2010, methodology): “Hagenaar (2001) studied the properties of ephemeral regions using the SOHO/MDI instrument and found far more (smaller) ephemeral regions with a rate of emergence sufficient to replace the quiet Sun magnetic field in just 14 hours.”
Solar Fine-Scale Structures. I. Spicules and Other Small-Scale, Jet-Like Events at the Chromospheric Level: Observations and Physical Parameters (2012, methodology): “Using a series of full-disc 96 minute MDI magnetograms, Hagenaar (2001) found that the time taken for all flux within the quiet Sun photosphere to be replaced (“the flux replacement timescale”) was around 14 hours.”
Modeling the Sun’s Magnetic Field and Irradiance since 1713 (2005, background): “If instead we follow Hagenaar (2001) by taking df /dt ¼ 5 ; 1023 Mx day 1 and f0 ¼ 1:13 ; 1019 Mx, we find that k 1:5 s 22;000 km, ’ 6:8 hr (roughly consistent with the value of 4.4 hr measured by HarveyAngle 1993), and Beph ’ 2:3 G.”
SIMULATION OF THE FORMATION OF A SOLAR ACTIVE REGION (2010, background): “Observations of active regions on the solar surface indicate that, in terms of magnetic flux content, there is a continuous spectrum of active region sizes (Zwaan 1978, 1987; Harvey & Martin 1973; Schrijver & Zwaan 2000; Hagenaar 2001; Hagenaar et al. 2003).”
The magnetic field in the solar atmosphere (2014, background): “As a consequence, the magnetic flux in the quiet-Sun photosphere is replaced every ≈14 h (Hagenaar 2001).”
Secular variation of the Sun's magnetic flux (2002, methodology): “For the corresponding decay time of the ER flux we take the value τeph = 14 h given by Hagenaar (2001).”
Reconstruction of solar total irradiance since 1700 from the surface magnetic flux (2007, methodology): “(6) can be estimated in the following manner: X = εeph,max εeph,min εeph,min εact,max · (8) Here εeph,min = 1.8 × 1026 Mx yr−1 (Hagenaar 2001), εact,max = 2.3 × 1024 Mx yr−1 (Schrijver & Harvey 1994), and values of εeph,max/εeph,min found in the literature lie in the range 1–2 (Harvey 1993, 1994b;…”
A Flux-Tube Tectonics Model for Solar Coronal Heating Driven by the Magnetic Carpet (2002, methodology): “The Life History of Photospheric Magnetic Flux Results from the MDI instrument on SOHO by Schrijver et al. (1998), Schrijver & Zwaan (2000), and Hagenaar (2001) have shown that the surface of the Sun is covered with a magnetic carpet, in which magnetic fragments are continually emerging,…”
Solar Surface Emerging Flux Regions: A Comparative Study of Radiative MHD Modeling and Hinode SOT Observations (2008, methodology): “In this paper, we extend our previous study to flux tubes with a flux on the order of 1020 Mx, comparable to the flux content of mid-sized ephemeral regions (Hagenaar 2001).”
Magnetic flux emergence in granular convection: radiative MHD simulations and observational signatures (2007, background): “For instance, almost all the flux of a large active region emerges within the first ∼ 4 ∗ Present address: Lockheed Martin Solar and Astrophysics Laboratory, Bldg/252 3251 Hanover St., Palo Alto, CA 94304, USA. days of their development (Zwaan, 1985; Hagenaar, 2001).”