Who is mausumi dikpati

The field lines rise to the surface at low latitudes and form bipolar sunspots, which are regions of concentrated magnetic fields. When these sunspots decay, they imprint the moving plasma with a type of magnetic signature. As the plasma nears the poles, it sinks about , kilometers , miles back into the convection zone and starts returning toward the equator at a speed of about one meter three feet per second or slower.

The increasingly concentrated fields become stretched and twisted by the internal rotation of the Sun as they near the equator, gradually becoming less stable than the surrounding plasma. This eventually causes coiled-up magnetic field lines to rise up, tear through the Sun's surface, and create new sunspots. The subsurface plasma flow used in the model has been verified with the relatively new technique of helioseismology, based on observations from both NSF— and NASA—supported instruments.

This technique tracks sound waves reverberating inside the Sun to reveal details about the interior, much as a doctor might use an ultrasound to see inside a patient. Large-scale solar dynamo models were first built by Parker Over the past half a century these models have evolved significantly. It is widely accepted that the large-scale coronal structure is governed by magnetic fields that are most likely generated by dynamo action in the solar interior.

In order to understand the variation in coronal structure, we couple a potential-field Solar cycle 23 behaved differently than cycle 22 in many ways. Certain properties, namely the long minimum at the end of cycle 23, weakening of polar fields, shrinking of polar coronal holes, reduction in the terrestrial atmospheric neutral density layer, have been identified as unusual compared to several past cycles.

The origin of these differences most likely lies in the ways the dynamo has operated Flux-transport type solar dynamos have achieved considerable success in correctly simulating many solar cycle features, and are now being used for prediction of solar cycle timing and amplitude. We first define flux-transport dynamos and demonstrate how they work. The essential added ingredient in this class of models is meridional circulation, which governs the dynamo period and also plays a crucial Gilman , Giuliana de Toma , Siddhartha S.

Phase speed of magnetized Rossby waves that cause solar seasons. Role of interaction between magnetic Rossby waves and tachocline differential rotation in producing solar seasons. The origin of the "seasons" in space weather.

An observationally constrained 3D potential-field source-surface model for the evolution of longitude-dependent coronal structures. North—South asymmetry in Rieger-type periodicity during Solar Cycles 19— Role of response time of a Babcock-Leighton solar dynamo model in meridional flow-speed reconstruction by EnKF data assimilation.

Data assimilation in a solar dynamo model using ensemble Kalman filters: Sensitivity and robustness in reconstruction of meridional flow speed.

The solar cycle and solar dynamo models: Past accomplishments, present status and a strategy for the 21st century. Cyclic evolution of coronal fields from a coupled dynamo potential-field source-surface model. Recent advances on solar global magnetism and variability. A Babcock-Leighton solar dynamo model with multicellular meridional circulation in advection- and diffusion-dominated regimes. Observations and modeling of north-south asymmetries using a flux transport dynamo.

Ensemble Kalman filter data assimilation in a Babcock-Leighton solar dynamo model: An observation system simulation experiment for reconstructing meridional flow speed. A three-dimensional Babcock-Leighton solar dynamo model. Generating the Sun's global meridional circulation from differential rotation and turbulent Reynolds stresses. Role of asymmetric meridional circulation in producing north-south asymmetry in a solar cycle dynamo model. Exploring the North-South asymmetry in a Babcock-Leighton dynamo.

Evaluating potential for data assimilation in a flux-transport dynamo model by assessing sensitivity and response to meridional flow variation. Therory of solar meridional circulation at high latitudes. Nonlinear evolution of global hydrodynamic shallow-water instability in the solar tachocline. Plasma flow versus magnetic feature-tracking speeds in the Sun. Sunspot activity has continued to decline throughout and as of mid, there have been few detectable sunspots.

Wikimedia Foundation. Solar maximum — or solar max is the period of greatest solar activity in the solar cycle of the sun.