Physical Models of the Lunar Wake and Data-Model Comparisons

• Author / Creator

  Gharaee, Hossna

• In this thesis, the lunar wake is investigated with a hybrid-kinetic model to simulate the dynamics of the ions as particles as well as in the fluid approximations. Two-fluid models of the entire wake whether interacting (the method of characteristics) or not (the analytic model) are developed based on a simple single-fluid description of only one edge of the lunar wake.
  A finite element code is also used to study the lunar wake as a single-fluid and with the two-fluid interacting and, two-fluid non-interacting models.
  All these models are two dimensional, in a plane of the solar wind velocity and the interplanetary magnetic field (IMF). The orientation of the IMF is one of the essential elements controlling the formation of the wake and is discussed in this thesis. To validate these models, two different IMF oriented in-situ observations of the density in the lunar wake from the ARTEMIS mission are presented. Cross-comparisons between densities calculated by these models are also provided. These 2D models can capture the conical shape of the lunar wake, the density depletion, and the relation between the length of the wake and the IMF orientation. However, the formation of the standing shock wave behind the Moon can only be seen from the finite element approach. A relatively good qualitative and quantitative agreement between the results of the observations and each model is achieved. To check the consistency of the assumptions made in the fluid model, a test particle method is applied to calculate the distribution function of the ions on their trajectories in the terminator very close to the Moon surface by using the approximate fields from an analytic model. The calculated macroscopic variables from the distribution functions are compared with the ones assumed in the analytic-fluid description, and an excellent agreement is obtained.

• Subjects / Keywords

  • Analytic model
  • ARTEMIS observations
  • Selenocentric Solar Ecliptic (SSE) coordinates
  • Test-particle simulations
  • Method of characteristics
  • Downstream
  • Lunar wake
  • Hybrid-kinetic model
  • two-fluid models
  • Counterstreaming fluids
  • Finite Element Model
  • Moon

• Graduation date

  Fall 2019

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/r3-0nb7-0150

• License

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