Geoscience Reference
In-Depth Information
As curves 3-5 show, to determine the turbulence parameter with better
confidence, measurements at energies
>
10 keV are much desired. Extend-
ing the modeling energy to beyond 100 keV is especially useful, when
linking ACR acceleration at heliospheric boundaries via the detection of
ENA with solar modulation of cosmic rays via the detection of ACR, both
at 1 AU.
31
Both models
29
,
30
cited above show the usefulness of ENA observation
at 1 AU, in both cases, by HSTOF on SoHO at L1, to modeling the ions
in far-away heliospheric boundaries, even when the instrument has a lim-
ited energy window and can only detect ENA under quiet conditions set
by Sun's activities. These models and the SoHO measurements focus on
the acceleration of superthermal PUI to become ACR at the heliospheric
boundaries. The upcoming IBEX has a different goal and requires different
models.
2.2.2.
In anticipation of the IBEX mission
Expected H fluxes from the heliospheric boundaries anticipated in IBEX's
energy range (0.01-6 keV) depend on the nature and structure of TS and,
also, on the evolution of PUI in the supersonic solar wind, at TS and in
HS. Gruntman
et al
.
33
have considered several scenarios and calculated
H fluxes in different directions as functions of energy. More exact multi-
component models have been published
3
,
34
,
35
based on the heliospheric
interface modeled by Baranov and Malama.
6
The latest model
34
,
35
treats
different groups of PUI separately from the bulk solar wind, and takes
into account of all the participating particles ranging from galactic and
anomalous cosmic rays to different species of ions in the magnetized inter-
stellar and solar plasmas, in a multi-component and kinetic-continuum
computational approach to set the location, shape, and particle distri-
butions of the boundary layers, thus providing the most comprehensive
model of the heliosphere. Protons from different origins are injected to
produce the different H fluxes. The dominant components are presented
in Fig. 4.
34
,
35
Curve 0 shows the flux coming from solar-wind protons in
the inner HS. Curves 1 and 2 correspond to fluxes originated from two
types of pickup protons in HS (see details in Ref. 34). Curve 3 represents
secondary interstellar H flux. For comparison, curve BM is the result of
the one-component model.
6
Two-dimensional images of the entire helio-
sphere in neutral H flux based on a similar but simpler model have been
produced.
33
