Solar cycle influence on the interaction of the solar wind with Local Interstellar Cloud

Abstract

Abstract. We present results of a new time-dependent kinetic model of the H atom penetration through the solar windinterstellar medium interaction region. A kinetic 6D (time, two dimensions in space, and three dimensions in velocity-space) equation for interstellar H atoms was solved self-consistently with time-dependent Euler equations for the solar wind and interstellar charged components. We study the response of the interaction region to 11-year solar cycle variations of the solar wind dynamic pressure. It is shown that the termination shock location varies within ±7 AU, the heliopause variation is ∼4 AU, and the bow shock variation is negligible. At large heliocentric distances, the solar cycle induces 10-12% fluctuations in the number density of both primary and secondary interstellar H atoms and atoms created in the inner heliosheath. We underline the kinetic behavior of the fluctuations of the H atom populations. Closer to the Sun the fluctuations increase up to 30-35% at 5 AU due to solar cycle variation of the charge exchange rate. Solar cycle variations of interstellar H atoms in the heliospheric interface and within the heliosphere may have major importance for the interpretation of H atom observations inside the heliosphere.

STABILITY OF A PICKUP ION RING-BEAM POPULATION IN THE OUTER HELIOSHEATH: IMPLICATIONS FOR THEIBEXRIBBON

“…In addition to interstellar turbulence waves may be excited due to large-scale motions in the OHS. Some possible drivers include the solar wind large-scale transient structures and the solar-cycle dynamic pressure variations (Zank & Müller 2003;Scherer & Fahr 2003;Izmodenov et al 2005), and the instability of the heliopause due to a difference in charge-exchange rates across the boundary (Liewer et al 1996;Zank et al 1996;Florinski et al 2005;Borovikov et al 2008). The scale of these motions is expected to be significantly shorter than the interstellar turbulent scales, perhaps on the order of 50 AU.…”

Magnetic Fields in the Heliosheath and Distant Heliosphere:Voyager 1and2Observations During 2005 and 2006

“…Estimates of thickness of the heliosheath in the nose direction vary depending on the interstellar magnetic field and the pressure of the interstellar plasma at the heliopause (which have not been measured directly), the model used, and the direction. Izmodenov et al (2005) and Izmodenov & Alexashov (2006) estimate a width %52-75 AU in the direction that V1 is moving, Opher et al (2006) estimate a width of %55-59 AU at V1, and Müller et al (2006) estimate that the ratio of the distance to the heliopause to that of TS is %1.4 in the nose direction, giving a thickness of the order of 40 AU in that direction; the thickness of the heliosheath increases away from the nose direction. Estimates of B in the heliosheath near the heliopause in the vicinity of the nose are of the order of 0.6 nT.…”

“…The heliosheath is a region extending from the termination shock to the interstellar medium (Axford 1972;Parker 1963;Hundhausen 1972;Zank 1999). Models of the termination shock and heliosheath have been presented by Liewer et al (1993Liewer et al ( , 1996, Leroy (1983), Whang et al (1995), Pauls et al (1995), Müller et al (2006), Opher et al (2004Opher et al ( , 2006, Izmodenov et al (2005), Izmodenov & Alexashov (2006), Nerney et al (1991Nerney et al ( , 1993Nerney et al ( , 1995, Pogorelov (2006), Pogorelov et al (2006), Washimi (1993), Washimi & Tanaka (1996, 1999, , Zank (1999), and Zank et al (1996). A significant feature of the magnetic fields observed in the heliosheath is the large variability of the magnetic field strength B.…”

Ibex Observations of Secondary Interstellar Helium and Oxygen Distributions

“…As discussed in Section 4.1, the final peak longitude of the secondary He population may fall between the two peak longitudes derived from the different approaches, depending on how much each of the approaches is affected systematically. Therefore, the exact l According to a global heliospheric model by Izmodenov et al (2005), the typical plasma bulk speed is ∼4 km s −1 Sunward along the upwind direction in the outer heliosheath. As an estimate of the typical speeds of the secondary populations in the outer heliosheath, we take the sum of the plasma bulk and thermal speed:…”

“…Izmodenov et al (2005) also stated that the plasma temperature increases to ∼35,000 K in the outer heliosheath, and Kubiak et al (2016) estimated a Warm Breeze temperature of ∼9500 K based on the IBEX observations. For these two temperatures, the typical speeds of the secondary He population in the outer heliosheath would be approximately 18 km s −1 and 11 km s −1…”