biostudies-literatureHolappa LNational Aeronautics and Space AdministrationLuonnontieteiden ja Tekniikan Tutkimuksen Toimikuntae2022GL098031https://www.ebi.ac.uk/biostudies/studies/S-EPMC9286478biostudies-literatureUnknown49(8)The most important parameter driving the solar wind-magnetosphere interaction is the southward (B z ) component of the interplanetary magnetic field (IMF). While the dawn-dusk (B y ) component of the IMF is also known to play an important role, its effects are usually assumed to be independent of its sign. Here we demonstrate for the first time a seasonally varying, explicit IMF B y -dependence of the ring current and Dst index. Using satellite observations and a global magnetohydrodynamic model coupled with a ring current model, we show that for a fixed level of solar wind driving the flux of energetic magnetospheric protons and the growth-rate of the ring current are greater for B y < 0 (B y > 0) than for B y > 0 (B y < 0) in Northern Hemisphere summer (winter). While the physical mechanism of this explicit B y -effect is not yet fully understood, our results suggest that IMF B y modulates magnetospheric convection and plasma transport in the inner magnetosphere.Geophysical research lettersExplicit IMF B y -Dependence of Energetic Protons and the Ring Current.PMC928647880NSSC19K0085322459Holappa LBuzulukova NYfalseExplicit IMF B y -Dependence of Energetic Protons and the Ring Current.The most important parameter driving the solar wind-magnetosphere interaction is the southward (B z ) component of the interplanetary magnetic field (IMF). While the dawn-dusk (B y ) component of the IMF is also known to play an important role, its effects are usually assumed to be independent of its sign. Here we demonstrate for the first time a seasonally varying, explicit IMF B y -dependence of the ring current and Dst index. Using satellite observations and a global magnetohydrodynamic model coupled with a ring current model, we show that for a fixed level of solar wind driving the flux of energetic magnetospheric protons and the growth-rate of the ring current are greater for B y < 0 (B y > 0) than for B y > 0 (B y < 0) in Northern Hemisphere summer (winter). While the physical mechanism of this explicit B y -effect is not yet fully understood, our results suggest that IMF B y modulates magnetospheric convection and plasma transport in the inner magnetosphere.2022-01-01T00:00:00Z2022 Apr2024-02-15T16:20:58.733Z2022-08-04T14:52:01.596ZS-EPMC92864783586606010.1029/2022GL098031