;+
;NAME:
; mvn_qlook_filename
;PURPOSE:
; Create s filename for a qlook plot
;CALLING SEQUENCE:
; filename = mvn_qlook_filename(intstrument, time_range, $
;                               date_only = date_only)
;INPUT:
; instrument = a string for the instrument, e.g., 'swia', 'swea',
;              etc...
; time_range = start and end times for the data
;OUTPUT:
; filename = a filename
; 'mvn_'+instrument+'_ql_'+date+start_hour+end_hour
;KEYWORDS:
; date_only =  if set, only put the start date in the filename
;HISTORY:
; jmm, 2013-06-05
;-
Function mvn_qlook_filename, instrument, time_range, date_only = date_only, alt_name = alt_name, _extra = _extra

trs = time_string(time_range, precision = -2, format=6)
date = strmid(trs[0], 0, 8)

start_hour = strmid(trs[0], 8, 2)
end_hour = strmid(trs[1], 8, 2)

If(keyword_set(date_only)) Then date_ext = date $
Else date_ext = date+'_'+start_hour+end_hour

If(keyword_set(alt_name)) Then Begin
    fname = 'mvn_'+instrument+'_l2_gen_'+date_ext+'_v00_r00'
Endif Else Begin
    fname = 'mvn_'+instrument+'_ql_'+date_ext
Endelse

Return, fname
End