IISER Kolkata study shows solar activity likely to peak in 2024

Kolkata: The Sun’s currently active phase of Solar Cycle 25 is likely to peak to its maximum intensity in 2024, as is evident in the increasing number of sunspots and increasing solar flare activity, according to researchers from IISER Kolkata.

The solar cycle is the period when the Sun's magnetic field flips every 11 years as it becomes more tangled like a ball of yarn.

Data from observations starting from the early 1600s show that approximately every 11 years, the number of spots and the intensity of solar activity reach a peak when the most violent perturbations in planetary space environments -- or space weather -- are expected.

This includes serious damage to orbiting satellites, electric power grids and telecommunications when directed toward Earth.

However, predicting when this peak is going to occur has remained challenging.

The team discovered a new relationship between the sun's magnetic field and its sunspot cycle that can help predict when the peak in solar activity will occur, they said in the research paper, appearing in the Monthly Notices of the Royal Astronomical Society: Letters.

In 1935, Swiss astronomer Max Waldmeier discovered that the faster the rate of rise of a sunspot cycle, the stronger its strength, so stronger cycles take less time to rise to their peak intensity. This relationship has often been utilised to forecast the strength of a sunspot cycle based on observations of its early rising phase.

The new discovery by the IISER team complements the Waldmeier effect, connecting the two primary magnetic field components of the sun and supporting the theory that the evolution of sunspots are integral to the functioning of the solar dynamo process rather than being a mere symptom of it.

These new observations of the rate of decrease of the sun's dipole magnetic field can be usefully combined with sunspot observations to predict when the ongoing cycle would peak.

The analysis suggests that the maximum of solar cycle 25 is most likely to occur in early 2024, with an uncertainty in the estimate that ranges to September 2024, the researchers said.

With this latest discovery, a new window opens up for forecasting the timing of the peak of solar cycles -- when the most intense activity and most frequent space weather disturbances are expected, they noted.