

Type of Document Dissertation Author Song, Degong Author's Email Address dsong@vt.edu URN etd-03072000-23200015 Title On the Spectrum of Neutron Transport Equations with Reflecting Boundary Conditions Degree PhD Department Mathematics Advisory Committee
Advisor Name Title Dr. William Greenberg Committee Chair Dr. George Hagedorn Committee Member Dr. Martin Klaus Committee Member Dr. Peter Haskell Committee Member Dr. Werner Kohler Committee Member Keywords
- transport equation
- spectrum
- stability
- strongly continuous semigroup
Date of Defense 2000-02-14 Availability unrestricted Abstract This dissertation is devoted to investigating the time dependent neutron transportequations with reflecting boundary conditions. Two typical geometries --- slab geometry
and spherical geometry --- are considered in the setting of L^p including L^1. Some
aspects of the spectral properties of the transport operator A and the strongly
continuous semigroup T(t) generated by A are studied. It is shown under fairly
general assumptions that the accumulation points of { m Pas}(A):=sigma (A) cap
{ lambda :{ m Re}lambda > -lambda^{ast} }, if they exist, could only appear on
the line { m Re}lambda =-lambda^{ast}, where lambda^{ast} is the essential
infimum of the total collision frequency. The spectrum of T(t) outside the disk {lambda : |lambda| leq exp (-lambda^{ast} t)} consists of isolated eigenvalues
of T(t) with finite algebraic multiplicity, and the accumulation points of
sigma (T(t)) igcap{ lambda : |lambda| > exp (-lambda^{ast} t)}, if they
exist, could only appear on the circle {lambda :|lambda| =exp (-lambda^{ast} t)}.
Consequently, the asymptotic behavior of the time dependent solution is obtained.
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