A NEW PHYSICALLY VIABLE FLUID CLOSURE FOR HEAT CONDUCTION IN A FULLY IONIZED PLASMA IS PROPOSED SUITABLE FOR A FINITE RATHER THAN INFINITESIMAL KNUDSEN NUMBER K WHERE K IS THE COULOMB MEAN FREE PATH FOR SCATTERING DIVIDED BY THE GRADIENT SCALE ALONG THE MAGNETIC FIELD. SUITABLE FOR THE FORMATION OF THE CORONA-WIND LARGE SCALE RECONNECTION SCENARIOS AND MODELING OF SPACE WEATHER EFFECTS THIS CLOSURE SUGGESTS A GENERAL DIRECTION FOR HEAT FLOW TO BE ALONG THE COMPONENT OF THE ELECTRIC FIELD PARALLEL TO THE MAGNETIC FIELD IN CONTRAST WITH SPITZER'S 1953 HEAT LAW FROM HOT TO COLDER TEMPERATURES. IN WEAK GRADIENTS THE NEW METHOD AGREES WITH SPITZER'S DIRECTION OF THE HEAT FLOW. HOWEVER SPITZER'S FORMULA IS ONLY VALID FOR VERY SMALL KNUDSEN NUMBERS K<0.01 IMPLYING R<1.05 RO. THE INDEFENSIBLE ARGUMENT THAT A PEAKED CORONAL T(R) REQUIRES ENERGY SUPPLY AT ITS MAXIMUM PRESUMES THE PHYSICALITY OF SPITZER'S MATHEMATICAL FORM ABOVE R>1.05RO WHERE ITS STRUCTURE IS UNKNOWN BEING OUTSIDE ITS DOMAIN OF KNUDSEN NUMBER VALIDITY. THE HEAT FLUX CLOSURE OF THIS PROPOSAL IS A REALIZATION OF A MORE GENERAL PRINCIPLE THAT PROPOSES A PARTITION OF (E)LECTRON (V)ELOCITY (D)ISTRIBUTION (F)UNCTION (EVDF) BASED ON THE PHYSICS OF SO-CALLED RUNAWAY EFFECT. IT IS BASED ON THE NEWLY RECOGNIZED INTERPLAY FOR FINITE K ASTRO-PLASMAS OF (I) TRANSPORT EFFECTS AND THE (II) DIMENSIONLESS PARALLEL ELECTRIC FIELD PHYSICS THAT CONTROLS (III) ELECTRON PLASMA RUNAWAY NOT ALLOWED IN SPITZER'S INFINITESIMAL K REGIME. THE DIMENSIONLESS ELECTRIC FIELD EE IS THE PARALLEL ELECTRIC FIELD SCALED BY DREICER S ELECTRIC FIELD. AS IDENTIFIED BY DREICER THE RUNAWAY ELECTRONS ARE THOSE THAT GAIN MORE ENERGY FROM THE ELECTRIC FIELD THAN THEY LOSE VIA COULOMB SCATTERING. THIS CONNECTION LEADS TO OUR MODELING THE ELECTRONS AS TWO INTERACTING SUB-FLUIDS WITH THEIR OWN FLUID SCALE EQUATIONS OF MOTION AND DISPARATE MEAN ENERGIES. THESE SUB-FLUIDS INTERACT WITH ONE ANOTHER FRICTIONALLY AND BY EXCHANGING DENIZENS AS EE VARIES IN SPACE ALLOWING THE PROPOSED CLOSURE TO BE FORMULATED AND QUANTITATIVE PREDICTIONS MADE REPLICATING 5 DECADES OF OBSERVATIONS ABOUT THE EVDF. TESTING OF THE PROPOSED CLOSURE DEMANDS EMPIRICAL KNOWLEDGE OF THE SIZE AND VARIATION OF (I) EE(R) THAT WE HAVE BEGUN TO DETERMINE FROM HELIOS RADIAL AND WIND VELOCITY SPACE PROFILES AND (II) THE THERMAL FORCE TF(R) THAT WE HAVE SHOWN CAN BE DETERMINED DIRECTLY FROM INDIVIDUAL SPECTRA ON A SINGLE SPACECRAFT. THE PROPOSED CLOSURE EQUATIONS INVOLVE TRADITIONAL FLUID VARIABLES BUT ALSO INCLUDE EE(R) TF(R) AND THE DRIFT SPEED OF THE LOWER ENERGY SUB-FLUID IN THE ION REST FRAME. TOGETHER THESE CLOSE THE LOGICAL LOOP BETWEEN MAKING THE FLUID PLASMA IN THE PRESENCE OF GRADIENTS QUASI-NEUTRAL WITH ZERO PARALLEL CURRENT SUPPORTING A HEAT FLUX AND CONTAINING THE TF THE KEYSTONE FOR A QUASISTEADY STATE THERMALLY CONDUCTING FLUID FLOW. TO OUR KNOWLEDGE THE PROPOSED CLOSURE IS THE ONLY PHYSICALLY VIABLE FLUID SCALE HEAT LAW SUITABLE FOR USE OUTSIDE OF 1.05RO INCLUDING ACROSS THE INNER LAYERS OF THE CORONA THE INCIPIENT ACCELERATION OF THE SOLAR WIND AND THE PLASMAS TO BE SAMPLED BY PARKER SOLAR PROBE AND SOLAR ORBITER. OUR MODEL EXPLAINS THE ORIGIN OF THE UBIQUITOUS NON-THERMAL FORM OF THE SOLAR WIND'S EVDF AND QUANTITATIVELY PREDICTS THE CORRELATIONS AND BULK SPEED DEPENDENCE OF ITS SHAPE PARAMETERS REPORTED OVER THE LAST 50 YEARS. THE SUGGESTED ORIGIN OF THE NON-THERMAL EVDF MOTIVATES THE THEORETICALLY UNUSUAL BUT DOMINANT ROLE THE SUPRATHERMALS PLAY IN DETERMINING THE SOLAR WIND HEAT FLOW. THESE SHAPE PARAMETERS AND THE HEAT FLUX IN OUR MODEL ARE DETERMINED BY THE NON-PERTURBATIVE SIZE OF EE. THE CULMINATING CLOSURE FOR THE HEAT LAW DEMONSTRATES HOW A STEADY STATE SOLAR WIND IS POSSIBLE WITHOUT PARALLEL CURRENTS DESPITE THE STRONG PARALLEL ELECTRIC FIELDS REQUIRED FOR QUASI-NEUTRALITY AND THE CONCOMITANT RUNAWAYS.