What the Sudden Death of Solar Cycles Can Tell Us About the Nature of the Solar Interior

McIntosh, Scott W.; Leamon, Robert J.; Egeland, Ricky; Dikpati, Mausumi; Fan, Yuhong; Rempel, Matthias

doi:10.1007/s11207-019-1474-y

Cited by 44 publications

(85 citation statements)

References 44 publications

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“…Можно предположить, что основную роль в увеличении количества спокойных дней в 24-м цикле солнечной активности играет не число солнечных пятен и групп пятен, а уменьшение напряженности их магнитного поля со временем . Не исключено, что процессы, происходящие внутри Солнца [McIntosh et al, 2019], также приводят к снижению солнечной активности и дают наблюдаемый эффект роста числа спокойных дней. В свою очередь, имеющая место тенденция к уменьшению солнечной и геомагнитной активности с 19-го по 24-й цикл может быть связана с приближением минимума 200-летнего цикла солнечной активности (2050-2060 гг.)…”

Section: Discussionunclassified

Global disturbance of Earth’s magnetosphere and its connection with space weather

Kurazhkovskaya

2020

Solnechno-Zemnaya Fizika

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This paper deals with extreme conditions of the global magnetosphere disturbance: very quiet and greatly disturbed, and their relationship with interplanetary medium parameters. The degree of global magnetosphere disturbance was estimated from the monthly and annual number of magnetically quiet and magnetically disturbed days. The cyclic and seasonal distributions of magnetically quiet and disturbed days were compared, and their relationship with interplanetary medium parameters in solar cycles 20–24 was analyzed. Magnetically quiet days are shown to be mainly observed at the ascending phase of solar activity and during the winter solstice season. Magnetically disturbed days dominate at the descending phase of the solar cycle and during the equinox season. An anomalously large increase in the number of quiet days was found in solar cycle 24 as compared to previous cycles. It has been established that the cyclic variation in the annual number of quiet and disturbed days is determined by the behavior and magnitude of the speed, temperature, dynamic pressure of solar wind plasma and the interplanetary magnetic field modulus. The detected burst in the number of quiet days during the ascending phase of solar cycle 24 is assumed to reflect internal processes on the Sun and related changes in interplanetary medium parameters. The patterns of cyclical and seasonal variation in the number of magnetically quiet and disturbed days and their relationship with the solar wind parameters can be used to predict space weather.

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Section: Discussionunclassified

Global disturbance of Earth’s magnetosphere and its connection with space weather

Kurazhkovskaya

2020

Solnechno-Zemnaya Fizika

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“…They are located between each solar cycle minimum and the maximum of the next cycle, and we set zero phase to be that of the average of the terminators as estimated by McIntosh et al (2019). Cycle terminators (McIntosh & Leamon, 2014, 2014,2019) have been identified based on multiple observations of coronal magnetic activity which indicate the end of one cycle of activity and the beginning of the next. The termination of a solar cycle, or terminator, has a three‐component global signature (McIntosh et al, 2019).…”

Section: Constructing the Solar Cycle Clockmentioning

confidence: 99%

“…Cycle terminators (McIntosh & Leamon, 2014, 2014,2019) have been identified based on multiple observations of coronal magnetic activity which indicate the end of one cycle of activity and the beginning of the next. The termination of a solar cycle, or terminator, has a three‐component global signature (McIntosh et al, 2019). It is initially observed as a very abrupt reduction in the density of extreme ultraviolet bright point density around the solar equator, marking the final cancelation of the old cycle's (magnetic) activity bands at the equator (McIntosh & Leamon, 2014).…”

Section: Constructing the Solar Cycle Clockmentioning

confidence: 99%

Quantifying the Solar Cycle Modulation of Extreme Space Weather

Chapman

McIntosh

Leamon

et al. 2020

Geophysical Research Letters

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By obtaining the analytic signal of daily sunspot numbers since 1818 we construct a new solar cycle phase clock that maps each of the last 18 solar cycles onto a single normalized 11 year epoch. This clock orders solar coronal activity and extremes of the aa index, which tracks geomagnetic storms at the Earth's surface over the last 14 solar cycles. We identify geomagnetically quiet intervals that are 40% of the normalized cycle, ±2π/5 in phase or ±2.2 years around solar minimum. Since 1868 only two severe (aa>300 nT) and one extreme (aa>500 nT) geomagnetic storms occurred in quiet intervals; 1–3% of severe (aa>300 nT) geomagnetic storms and 4–6% of C‐, M‐, and X‐class solar flares occurred in quiet intervals. This provides quantitative support to planning resilience against space weather impacts since only a few percent of all severe storms occur in quiet intervals and their start and end times are quantifiable.

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“…There is accumulating observational evidence that the Sun's atmosphere is also home to Rossby waves (see, e.g., McIntosh et al, 2017, and references therein; see also Krista et al, 2018;Loptien et al, 2018;Hanasoge & Mandal, 2019;Liang et al, 2019;McIntosh et al, 2019). Compared to the Earth's waves, solar Rossby waves appear to be strongly influenced by the presence of magnetic fields-those are almost ubiquitous in the Sun's atmosphere.…”

Section: Introductionmentioning

confidence: 99%

Space Weather Challenge and Forecasting Implications of Rossby Waves

Dikpati

McIntosh

2020

Space Weather

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Rossby waves arise in thin layers within fluid regions of stars and planets. These global wave‐like patterns occur due to the variation in Coriolis forces with latitude. In the past several years observational evidence has indicated that there are also Rossby waves in the Sun. Although Rossby waves have been detected in the Sun's photosphere and corona, they most likely originate in the solar tachocline, the sharp shear layer at the base of the solar convection zone, where the differential rotation driven by convection transitions to the solidly rotating radiative interior. These waves differ from their Earth's counterparts by being strongly modified by toroidal magnetic fields in the solar tachocline. Recent simulations of magnetohydrodynamics of tachocline Rossby waves and magnetic fields are demonstrated to produce strong “tachocline nonlinear oscillations,” which have periods similar to those observed in the solar atmosphere—enhanced periods of solar activity, or “seasons”—occurring at intervals between six months and two years. These seasonal/subseasonal bursts produce the strongest eruptive space weather events. Thus, a key to forecasting the timing, amplitude, and location of future activity bursts, and hence space weather events, could lie in our ability to forecast the phase and amplitude of Rossby waves and associated tachocline nonlinear oscillations. Accurately forecasting the properties of solar Rossby waves and their impact on space weather will require linking surface activity observations to the magnetohydrodynamics of tachocline Rossby waves, using modern data assimilation techniques. Both short‐term (hours to days) and long‐term (decadal to millennial) forecasts of space weather and climate are now being made. We highlight in this article the potential of solar Rossby waves for forecasting space weather on intermediate time scales, of several weeks to months up to a few years ahead.

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What the Sudden Death of Solar Cycles Can Tell Us About the Nature of the Solar Interior

Cited by 44 publications

References 44 publications

Global disturbance of Earth’s magnetosphere and its connection with space weather

Global disturbance of Earth’s magnetosphere and its connection with space weather

Quantifying the Solar Cycle Modulation of Extreme Space Weather

Space Weather Challenge and Forecasting Implications of Rossby Waves

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