Solar cycles

Triggering the Birth of New Cycle's Sunspots by Solar Tsunami

Image depicting global tachocline fluid top surface deformations
Monday, February 18, 2019

We demonstrate a novel physical mechanism, namely, that a “solar tsunami” occurring in the Sun’s interior shear-fluid layer can trigger new cycle’s magnetic flux emergence at high latitudes, a few weeks after the cessation of old cycle’s flux emergence near the equator.

The Extended Solar Cycle: Muddying the Waters of Solar/Stellar Dynamo Modeling Or Providing Crucial Observational

Graph depicting extended solar cycles
Monday, December 3, 2018

In 1844 Schwabe discovered that the number of sunspots increased and decreased over a period of about 11 years, that variation became known as the sunspot cycle.

Ionospheric Electron Content during Solar Cycle 23

Comparison of measured to modeled global total electron content
Tuesday, March 13, 2018

Solomon & Qian show that solar minima are not all the same, and may have implications for understanding the Sun during the extended periods of very low activity known as “grand minima” that have sometimes occurred in the past, the best known of which was the Maunder Minimum during 1650–1700.

EOS & Space Weather Feature McIntosh Archive Project

The McIntosh Archive project gets double notice: it's the subject of a recent highlight by EOS spotlight, which profiles a feature article for the journal Space Weather by Webb et al.

Origins of the Ambient Solar Wind: Implication for Space Weather

Carrington rotation stack plots
Thursday, September 7, 2017

The Sun’s outer atmosphere is heated to temperatures of millions of degrees, and solar plasma flows out into interplanetary space at supersonic speeds. This paper reviews our current understanding of these interrelated problems: coronal heating and the acceleration of the ambient solar wind.

Deciphering Solar Magnetic Activity: Spotting Solar Cycle 25

Comparing the evolution of the daily hemispheric sunspot number and a data-inspired representation of activity band polarity and migration image
Friday, June 9, 2017

We present observational signatures of solar cycle 25 onset. Those signatures are visibly following a migratory path from high to low latitudes.

Solar Cycle Variability Induced by Title Angle Scatter in a Babcockl-Leighton Solar Dynamo Model

Variability in sunspot number (SSN) in STABLE dynamo simulations of the solar cycle using the observed random scatter in sunspot pair tilt angle of 15 degrees. (a) 19 magnetic cycles are highlighted with red and blue representing the northern and southern hemispheres respectively. Red shaded areas indicate periods when the SSN in the north exceeds that in the south and blue shaded areas indicate the opposite. (b) Long-term SSN variability in the same simulation, exhibiting extended periods of low and high a
Saturday, April 15, 2017

We present results from a three-dimensional Babcock–Leighton dynamo model that is sustained by the explicit emergence and dispersal of bipolar magnetic regions (BMRs). On average, each BMR has a systematic tilt given by Joy’s law.

DKIST: Solar Physics in Service of Society

Phil Judge, Claire Raftery, Sarah Jaeggli

Philip Judge, Senior Scientist at HAO, Claire Raftery, Director of Education and Outreach at NSO HQ in Boulder, and Sarah Jaeggli, Assistant Astronomer at the NSO's Daniel K Inouye Solar Observatory in Maui were guests on KGNU public radio in Boulder, CO.

Lisa Upton

Lisa is a Visiting Scientist here at HAO since September 2014 and also is currently working for Space Systems Research Corporation. In the spring of 2017, Lisa will begin a NSF postdoctoral fellowship at HAO, working as a collaborator with the dynamo group.


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