The outer heliosphere, where the solar wind meets and interacts with the local interstellar medium, represents the current boundary between space physics and astrophysics. Study of the outer heliosphere requires the consideration of both kinetic and MHD physics. The kinetic physics is related to pickup ions, heating, turbulence, acceleration of energetic particles called the ``anomalous cosmic rays'', and the production of radio emissions. The fluid or MHD physics involves the macroscopic plasma structures and boundaries in the outer heliosphere (e.g., the termination shock and heliopause), evolved CIRs and CMEs called ``global merged interaction regions'', and the effects of pickup ions in slowing and heating the flow. The characteristics of the local interstellar medium are also of interest, especially remote sensing of the properties thereof.
This Lecture proceeds by summarising the properties of the solar wind and interstellar pick-up ions, discussing the remotely determined properties of the ``very local interstellar medium'' (VLISM), describing the global plasma boundaries and structures and estimating their likely locations based on various models, discussing the termination shock and global simulations of the outer heliosphere, and then joining these seemingly disparate concepts into a discussion of radio emissions that seem to be triggered by travelling solar disturbances in the vicinity of the heliopause.