• It is believed that the “solar dynamo” — a naturally occurring generator which produces electric and magnetic fields in the sun — is linked to the production of sunspots.
  • What kick-starts the 11-year sunspot cycle is not known.
  • Now, a group of solar physicists suggests that a “solar tsunami” is at work that triggers the new sunspot cycle, after the old one ends.
  • The extreme temperature and pressure conditions that prevail some 20,000 km below the sun’s surface cause its material to form a plasma consisting primarily of hydrogen and helium in a highly ionised state.
  • The plasma is confined with huge magnetic fields inside the sun.
  • The [sun’s] toroidal magnetic field, from which sunspots get generated, wraps around the sun in the east-west direction

Tell us more about the Celestial rubber bands

  • These magnetic fields behave like rubber bands on a polished sphere.
  • They tend to slip towards the poles.
  • Holding these fields in their place requires that there is extra mass (plasma mass) pushing at the bands from higher latitudes.
  • Thus, a magnetic dam is formed which is storing a big mass of plasma.
  • At the end of a solar cycle, this magnetic dam can break, releasing huge amounts of plasma cascading like a tsunami towards the poles.
  • These tsunami waves travel at high speeds of about 1,000 km per hour carrying excess plasma to the mid-latitudes.
  • There they give rise to magnetic flux eruptions.
  • These are seen as the bjustify patches that signal the start of the next cycle of sunspots.
  • The tsunami waves can traverse the required distance in a few weeks, unlike in earlier models.
  • The solar cycle and sunspot activity are intimately connected with space weather.
  • The model provides a sound physical mechanism supporting why we should expect the next sunspot cycle 25 to begin in the year 2020, followed by a strong increase in space weather shortly after the trigger of a series of new sunspots in that year.